AIMS OF ANTENATAL CARE

The aims of antenatal care are to ensure that:

PRECONCEPTION ADVICE

Ideally all women planning to become pregnant should be seen before conception. This visit gives the opportunity to review her personal and family history and to optimize control of conditions, such as hypertension or diabetes, before pregnancy.

It is also an opportunity to outline her antenatal care options and to discuss the tests she will be offered during the pregnancy, for example, screening for chromosome anomalies. If there is a history of congenital or genetic abnormalities referral to a genetics clinic can be arranged. If the woman is overweight or underweight she can be given appropriate dietary and exercise advice and be offered referral to a dietitian. The immune status of the woman can also be explored, particularly relating to her ABO group and Rhesus factor, and immunity to rubella, hepatitis B and C and varicella.

All women should be advised to take 0.4 mg of folate in the weeks before becoming pregnant and for the first 3 months of pregnancy to reduce the risk of a neural tube defect. Women with a past history of spina bifida or anencephaly should increase their daily intake of folate to 4 mg/day. Women who smoke should be strongly encouraged and supported to quit, for the reasons detailed later. If her partner also smokes he should also be encouraged to access a QUIT programme.

ANTENATAL CARE PROVIDERS

The providers of antenatal care may be a general practitioner, an obstetrician or a midwife. In many centres antenatal care is now provided by a team comprising midwives, hospital-based obstetricians and community general practitioners, each member of the team contributing their particular skills and expertise. The antenatal care may take place in a doctor’s rooms, in a hospital clinic, or in a clinic conducted by a midwife. The opportunity should be available for an expectant mother to choose which facility she would prefer, but she should know that, if a complication should arise, she would be transferred, if necessary, quickly and efficiently, to a facility staffed by experienced obstetricians.

Whichever facility a pregnant woman has chosen she should have the opportunity to talk to a health professional about matters that concern her during the pregnancy in an unhurried way and have her questions answered by an informed, communicative doctor and midwife.

PSYCHOLOGICAL PREPARATION FOR MOTHERHOOD

Some women appear confident that their pregnancy will proceed normally and that the birth of the baby will be easy. Most women, however, have concerns about the pregnancy and the process of childbirth. In the early weeks many women fear that the pregnancy may terminate as a miscarriage. Later in pregnancy many women fear that the baby will be malformed or retarded, or that childbirth will be dangerous and painful. A few women are concerned that after the birth they will not be able to regain their prepregnancy body shape. These fears may not be expressed unless the woman feels confident that she is able to ask her doctor about them and expect to receive a reasoned answer. Fears about the difficulty and pain of childbirth can be reduced by simple explanations of the nature and course of labour.

Women who obtain social and psychological support during pregnancy are less likely than those who do not, to have negative feelings about their pregnancy and the forthcoming birth. They are more likely to feel that they are ‘in control’ during the pregnancy, to have a worry-free childbirth, to communicate more effectively with their doctor or nursing staff, and to be more satisfied with the care they receive.

Many women are helped by antenatal classes, run either in conjunction with antenatal clinics or privately. The importance of providing written information in the woman’s primary language cannot be overstated.

DIET IN PREGNANCY

Many pregnant women are confused about what they should eat during pregnancy to make sure that they and their baby are properly nourished. What should a pregnant woman eat? To a large extent this will depend on her cultural background, her usual eating behaviour and her income level. As a general principle, women should be advised to eat a well-balanced diet that includes a sufficient amount of each of the five core food groups. It should be low in fat and high in fibre, with sufficient fresh fruit and vegetables, as is suitable for the general population and for her family. Although many women will eat slightly more during pregnancy there is no good evidence that they should drastically alter or increase their food intake. Table 6.1 shows the mean daily intake or RDI (recommended daily intake) that women should try to achieve. Table 6.2 shows what a pregnant woman should try to eat each day, translated into the foods a household buys.

Table 6.1 Recommended daily intakes

* Indicates an increased requirement compared to non-pregnant female 19–54 years

† Daily requirement is doubled to 400 μg daily. RDI = 200 μg in a non-pregnant female 19–54 years

‡ RDI is expressed as a range to account for differences in bioavailability in foods. RDI is for second and third trimesters

Table 6.2 A healthy diet

Most pregnant women who eat a sensible diet do not need vitamin supplements, with the exception of folate. It is now recommended that a woman who intends to become pregnant should take folate 0.5 mg a day for 3 months prior to conception and during the first trimester. Generally high-folate foods should be encouraged, such as plenty of fresh fruit and vegetables, and fortified breakfast cereals, as well as a folic acid supplement, as it is generally difficult to obtain this extra folate without a supplement. Women carrying a multiple pregnancy should continue taking folate throughout.

Healthy women living in the industrialized countries whose haemoglobin is within the normal range and who eat a sensible diet usually do not require iron supplements. However, many women routinely supplement their diet with iron, as they may find it difficult to eat enough iron-rich foods and are at risk of iron deficiency. A protective factor in pregnancy is that dietary iron absorption is also increased. Iron-rich foods, such as red meat, legumes/pulses, wholegrain breads and cereals and fortified breakfast cereals, should be encouraged as well as including vitamin C-rich foods with those foods containing iron to aid in the absorption of iron. High-risk women in developed countries, such as: women on a limited budget; women with fad food behaviours or eating disorders; vegan/vegetarian women; and most women living in the developing countries require iron supplementation. This is discussed in Chapter 15.

Excess vitamin A during pregnancy may also be harmful to the fetus, so care must be taken not to exceed the recommended daily intake of vitamin A. The best advice is for women to avoid vitamin supplements that contain vitamin A and other rich sources of vitamin A, such as liver. If they want to take a supplement they should be advised to choose a specific pregnancy multi-vitamin that does not contain vitamin A.

Calcium requirements are increased from 800 to 1100 mg calcium per day. This is usually met quite easily by an intake of three servings of calcium-rich foods daily. As with iron, the absorption of calcium from the diet is increased during pregnancy. Occasionally a woman may choose or be prescribed additional calcium.

Vitamin D stores may be inadequate in women who have restricted exposure to sunlight, who have a diet low in oily fish, eggs and meat or who are obese. These women should be advised to take 10 μg of vitamin D daily.

Another important food issue in pregnancy is for women to practise good food hygiene and food safety. This includes basic advice such as storing, preparing and cooking foods at the appropriate temperatures, and avoiding foods that may not be cooked thoroughly, i.e. foods from takeaway shops, meat pies and salads. The avoidance of uncooked foods such as soft cheese and raw fish is also prudent. The rationale for this is to ensure that all food is uncontaminated by food-borne bacteria, particularly Listeria, which may be harmful for the fetus.

ANTENATAL SCREENING

A great deal of prenatal care is spent in detecting potentially dangerous conditions early; screening is one strategy used. In its simplest form blood pressure measurement is a screening strategy, and is discussed later. Currently, much interest is being shown in screening for congenital defects, such as Down syndrome, neural tube defects and single gene defects, using DNA probes (Box 6.1).

Screening for genetic defects

Screening for Down syndrome and certain other genetic defects (for example cystic fibrosis, thalassaemia, haemophilia, Huntington’s disease, some muscular dystrophies) can be carried out by chorionic villus sampling or amniocentesis. Before using these methods, an ultrasound examination of the fetus is made to exclude gross abnormalities (Figs 6.1–6.3).

Fig. 6.1 Ultrasound scan showing a normal fetus at 8 weeks’ gestation.

Fig. 6.2 The scan shows an empty amniotic sac at 11 weeks’ gestation. The patient aborted 1 week later.

Fig. 6.3 Scan of a normally developing fetus at 12 weeks’ gestation. The measurement of nuchal thickness is within the normal range, indicating a very low risk of Down syndrome.

Chorionic villus sampling

A sample of chorionic tissue is removed from the placental edge between the 9th and 11th weeks of pregnancy by introducing a needle transabdominally and advancing it to the edge of the placenta under ultrasound guidance. About 20 mg of chorionic tissue is sucked into a syringe. The karyotype of the sample is determined within 48 hours.

Amniocentesis

The procedure is carried out at about the 15th week of pregnancy. A needle is thrust through the abdominal wall and into the amniotic sac, guided by ultrasound to avoid the placenta and fetus, and a sample of amniotic fluid is removed. This is centrifuged and the fetal cells obtained are cultured for 3 weeks. They are then harvested and a karyotype is made.

Chorionic villus sampling or amniocentesis?

The choice between chorionic villus sampling (CVS) and amniocentesis is controversial. CVS is performed in the first quarter of pregnancy and a preliminary karyotype result using FISH is obtained within 24–48 hours, so that parental anxiety about the result is reduced. However, the karyotyping is slightly less accurate than with amniocentesis because of potential contamination with cells of maternal origin, and the risk of abortion following CVS is slightly higher (1–3% above the background rate compared with 0.5–1% following amniocentesis). Concern has been expressed that CVS may be followed in late pregnancy by oligohydramnios and limb defects. A multicentre study of over 140 000 patients has shown no increase in these defects when CVS is compared to amniocentesis. On the other hand, the karyotype is only obtained 2 weeks after amniocentesis, which increases the psychological stress on the parents, and if the fetus is abnormal and termination of pregnancy is suggested, the process is more painful and psychologically disturbing.

Down syndrome and trisomy 18

Although the risk of Down syndrome and other trisomies, such as trisomy 18, is age related (Table 6.3), because the majority of babies are born to mothers under 35 most centres now offer screening to all women. Three screening regimens are commonly employed. The first calculates the risk using pregnancy-associated plasma protein A and free β-hCG levels at 9–13 weeks’ gestation, with the aim to take the serum sample at 10 weeks’. The second measures the nuchal thickness of the fetus between 11 weeks 0 days and 13 weeks 6 days: in about 80% of fetuses with Down syndrome there is increased fluid accumulation behind the neck (see Figs 6.4 and 6.5). The risk is then calculated using the nuchal thickness measurement combined with maternal age. The third method combines the levels of β-hCG, α-fetoprotein (AFP) and free unconjugated oestriol measured between 15 and 20 weeks. Oestriol and AFP levels are lower in fetuses with Down syndrome and β-hCG levels are raised. In some centres inhibin A levels are also used, as this increases the detection rate from 65% to 75–80%.

Table 6.3 The incidence of Down syndrome (T21) and trisomy 18 (T18) according to maternal age and gestational age. Note the fall between early pregnancy and birth, which is due to spontaneous pregnancy loss and to selective termination of pregnancy.

Fig. 6.4 Scan showing an enlarged nuchal thickness. CVS was then performed and established the diagnosis of Down syndrome.

Fig. 6.5 The profile of a normal 18-week fetus.

The combination of first trimester and nuchal translucency screening raises the detection rate from 70 to 90% without affecting the false positive rate of 5%.

If the risk of Down syndrome is calculated to be more than 1/200–250 the woman is then offered CVS if the gestation is between 11 and 14 weeks, or an amniocentesis if the gestation is more advanced.

Screening for open neural tube defects

Open neural tube defects (NTD) occur in two to five pregnancies per 1000. Because of the screening programme for Down syndrome and the use of second-trimester ultrasound scans, additional screening is not necessary

Counselling the patient

It is most important that the implications and details of these screening programmes are carefully explained to the couple, including the false positive and false negative rates. The counsellor must ensure that they clearly understand the difference between screening and diagnostic tests.

If an abnormal result is obtained they must then explain the possible consequences and the choices open to the parents. To reduce the couple’s anxiety they must be given sufficient time to absorb the information and have their questions clearly answered, avoiding medical jargon. The counsellor must inform, but not influence, the woman or her partner, who alone are responsible for making the decision whether to terminate or to continue the pregnancy.

ANTENATAL DEPRESSION

Between 5 and 10% of women develop depression at some time during their pregnancy, as judged by psychometric scales such as the Edinburgh Postnatal Depression Scale (EPDS). The vulnerable women tend to be primigravid, to have poor social support, to have either a partner who is unemployed or none at all, to be ambivalent about being pregnant or to be anxious about the health of their fetus. Vulnerable women require empathetic support from their attending health professionals and time to talk about their feelings when they are seen at an antenatal clinic or in a doctor’s rooms. These women are also likely to develop postnatal depression (see pp. 187–188).

CARE OF THE PREGNANT WOMAN

With this background information it is now possible to discuss the care of a pregnant woman. As mentioned in Chapter 1, most women have a good idea that they are pregnant when they visit a medical practitioner to confirm the diagnosis. At this visit the doctor will inquire about the present pregnancy, the history of previous pregnancies, family history, previous illnesses or infections (including genital herpes, varicella and HIV/AIDS) and other matters and will examine the woman as already described.

Two examinations require further discussion: blood pressure and weight, and whether the patient should be weighed at each antenatal visit.

FREQUENCY OF ANTENATAL VISITS

In 1929 there was, in Britain, increasing concern that the maternal mortality rate had not fallen since 1880 (when it was 5 per 1000 live births). This led to the formation of a committee which recommended that a pregnant woman should visit an antenatal clinic every 4 weeks to the 28th week of pregnancy, then every 2 weeks to the 36th week, and thereafter weekly until delivered. Much discussion has arisen recently regarding whether this 80-year-old recommendation is still appropriate. The number of visits can be safely reduced from the traditional 14 to 7–10 without increasing the risk of adverse perinatal outcomes. Using such a schedule the woman is first seen between weeks 7 and 10, and then between 12 and 15, 18 and 20, 26 and 28, and at 32, 34–36, 38, 40 and 41 weeks. If at any time abnormalities are detected the frequency of visits is adjusted accordingly.

Whatever schedule is adopted, a pregnant woman should be asked at each antenatal visit if she has any problems she wishes to discuss and if she is feeling fetal movements. She should have her blood pressure measured, her urine tested for protein where indicated, and the height of her fundus estimated (see Fig. 1.7, p. 7) or measured with a tape measure (Fig. 6.12) to evaluate the growth of the fetus. Once the fundus of the uterus can be palpated abdominally the fetal heart can be detected with a hand-held Doppler and women find it reassuring to hear the fetal heart at each visit. If an abnormal heart rhythm or rate is heard a formal ultrasound assessment of the fetal heart should be performed.

Fig. 6.12 Gestational age estimated from symphysis–fundal height.

In addition, after the 28th week the health professional customarily palpates the woman’s abdomen to determine the growth, presentation and position of the fetus. The technique used is discussed later in this chapter.

PREPARATION FOR BREASTFEEDING

During pregnancy the health professional should encourage the woman to breastfeed her infant. The benefits of breastfeeding should be discussed:

The health professional may provide the woman with a pamphlet about the breastfeeding support groups in her area.

Should the woman choose not to breastfeed, for whatever reason, the health professional should avoid making her feel guilty and should discuss the importance of preparing the breast-milk substitute according to the manufacturer’s directions.

GROWTH OF THE FETUS DURING PREGNANCY

As mentioned above, fetal growth can be determined roughly by the height of the fundus or the distance between the symphysis pubis to the top of the uterus. A more accurate assessment of the fetal growth and weight can be obtained by ultrasound imaging (Fig. 6.13), but this is only required in some pregnancies, for example if the doctor suspects that the fetus is either growth restricted or macrosomic or when medical complications associated with abnormal growth are present. Until about the 28th week of pregnancy the position of the fetal head (or buttocks) relative to the mother’s pelvis is of little clinical importance. After that time it becomes increasingly important, and should be monitored by the doctor or midwife. For the purposes of communication descriptive terms are used:

Fig. 6.13 Fetal weight at various weeks of gestation (from 24 weeks) among Scandinavian women as determined by ultrasound.

Fig. 6.14 The lie and presentation of the fetus.

Technique of abdominal examination

The patient assumes a reclining position, having emptied her bladder. The abdominal examination to the fetus is made by four ‘manoeuvres’, which are shown in Figures 6.15–6.18. The information is recorded in the patient’s antenatal records.

Fig. 6.15 First manoeuvre – fundal palpation. The height of the fundus is estimated and the fundal area gently palpated in an attempt to identify which pole of the fetus (breech or head) is occupying the fundus.

Fig. 6.16 Second manoeuvre – lateral palpation. The examiner’s hands slip gently down the sides of the uterus with quick palpation to try to identify on which side the firm back of the fetus or the soft belly and knobbly limbs can be detected.

Fig. 6.17 Pelvic manoeuvre. The examiner turns to face the patient’s feet and slides his hands gently on the lower part of the uterus, pressing down on each side to determine the presenting part. If it is the fetal head it can be ballotted between the fingers.

Fig. 6.18 Pawlik’s manoeuvre. This is not always necessary and must be performed gently. The presenting part is moved between the fingers and thumb of the examiner’s hand, to determine whether it is the fetal head or breech and the degree of descent into the maternal pelvis.

AGE AND REPRODUCTIVE PERFORMANCE

PREPARING FOR CHILDBIRTH

A woman who knows what to expect in childbirth is better able to cooperate and to find the experience less painful. Antenatal classes are available in many hospitals, and are provided by private obstetric physiotherapists for childbirth training. Childbirth training has broadened in recent years, along with the expansion of the original technique of psychoprophylaxis first developed in Russia. Psychoprophylaxis is based on the belief that fear and anxiety about pain and danger in childbirth, learned before the woman becomes pregnant and during pregnancy, sink deeply into her memory and produce a ‘conditioned reflex’. Because of this, every time a woman thinks of childbirth a mental image of pain and danger is conjured up, with the result that she enters labour anxious and tense. The tension and fear may increase the pain and delay the birth of the baby. Psychoprophylaxis seeks to eliminate the ‘conditioned reflex’ and to replace the negative image of childbirth with a more positive one. This is achieved by education during pregnancy in the hope that knowledge and insight will change the woman’s perceptions of labour. Psychoprophylaxis also seeks to alter the brain’s perception of pain and to convert it into a sensation of discomfort, which can be relieved by muscular activity. This is based on the concept of ‘pain dissociation’: pain becomes less intense if the woman keeps her mind busy by concentrating on something else. The suggested mental activity usually involves concentrating on a learned pattern of breathing, counting breaths, focusing on a particular point in the room, or consciously commanding the body to release its tension. However, it is very difficult for most women to maintain control and remain calm during the particularly painful stages of labour. The distraction techniques of psychoprophylaxis alone are therefore unrealistic and unsatisfactory for many women during childbirth.

As anthropologists, psychologists, physiotherapists and midwives have become increasingly active in the development of prepared childbirth, new strategies for pain management have been developed which offer more than the original psychoprophylaxis concept.

The social environment in which the baby will be born, and its effect on the woman, is now becoming an important consideration. Many women want their partner or some other ‘support person’ to be with them during childbirth. The presence of an informed loved one during labour gives the woman familiar and personal support to reduce the clinical environment of a delivery ward.

The discomfort and pain of childbirth are reduced if the attending nursing and medical staff treat the woman as an intelligent individual, who has needs and who can make choices, and who is perceived as a woman having a baby rather than as a patient requiring medical attention. Some hospitals are trying to make the place of birth as non-clinical as possible by providing a supportive environment with floor mattresses, functional beds, soft fabrics and colours, and a shower. These can reduce a woman’s anxiety and enable her to cope more efficiently with the process of childbirth.

Techniques of auditory and visual imagery or ‘mindfulness’ provide an additional means of managing pain in labour. Instead of dissociating from her pain (as in psychoprophylaxis) the woman uses the sensations of labour to assist her in creating an image of what is happening inside her body, allowing herself to feel the pain and let it go. For example, she may visualize her cervix opening each time she has a contraction; the baby’s head moving deeper into her pelvis; or the baby opening her vagina in the second stage of labour.

Another development has been the use of relaxation techniques. In psychoprophylaxis, relaxation is taught as a method of control. The woman uses quiet, controlled breathing to convince herself that she is not experiencing pain. More recently, relaxation has been used by the woman as a method of ‘letting go’ and so reducing the pain. She may move and rock to achieve relaxation; she may stamp her feet, or bang her fists to release stress and diffuse the pain. She may discover that for her, the most effective form of pain control is a combination of floor positions, rhythmic groaning and belly rocking.

The proponents of active involvement in childbirth believe that, if possible, the woman should be given a free choice in the position she wishes to adopt and the movements she wishes to make during labour and the birth of the baby. The woman may choose to lie on her side, to squat, or to position herself on her hands and knees. She may prefer to be supported in a nearly upright position, with her partner in front of or behind her. In this technique there is much less focus on breathing as an exercise or pattern, and more on breathing as a method that helps the woman ‘go with the flow’.

It is important to find out the woman’s preferred mode of behaviour, and to encourage her to use it in childbirth. A woman who is ‘tactile’, for example, will probably respond well to massage, hot packs applied to her back, and showers, and will tend to move about a good deal during labour. Other women prefer ‘visualization’, or eye-to-eye focusing, or will respond to key words such as ‘relax’, ‘go soft’, ‘let go’. A third group of women are able to relieve the pain of labour more effectively by using auditory strategies. They respond to their support person ‘pacing’ them during a contraction, and to giving themselves positive messages.

When a woman responds to the pain in a way she naturally prefers, her behaviour ceases to be due to a technique or a method. This reduces the anxiety that comes from having to perform a technique with which she is not comfortable, and which she fears she may not perform well.

The philosophy adopted by numbers of childbirth educators is to provide information and to give the woman permission to be herself. Some women prefer neither to attend classes nor to employ a private childbirth educator. For them, training videotapes are available which enable the woman and her partner to learn at home.

SIGNS THAT LABOUR IS ABOUT TO START

The signs that indicate that labour is soon to start or has started are described on page 68. An expectant mother should have these signs described to her or have access to a book that describes them, so that she can be comfortable knowing when she is probably in labour. A question asked by many women during an antenatal visit concerns whether they will be given drugs to relieve the pain of labour. They should be reassured that analgesics are readily available should they be requested. This matter is discussed on pages 82–84.

Many women are fearful that they will be left alone during the course of childbirth. Today, many women want their husband or partner or a ‘significant other person’ to be with them through the childbirth process, and most hospitals agree to this.

ANTENATAL INFORMATION

Certain matters affecting the mother during pregnancy should be discussed at the early visits.