History of present pregnancy

The date of the first day of the last menstrual period (or LMP) provides the clinician with an idea of how advanced the current pregnancy is, i.e. period of gestation. However, this information is often inaccurate as many women do not record the days on which they menstruate, unless the date of the period is associated with a significant life event or the woman has been actively trying to conceive. Hence, in addition to LMP, an ultrasound scan in the first or early second trimester should be used to date the pregnancy and to confirm the gestational age.

Menstrual history should also include the duration of the menstrual cycle as ovulation occurs on the 14th day before menstruation. The time interval between menstruation and ovulation (the proliferative phase of the menstrual cycle) may vary substantially, whereas, the post-ovulatory phase (secretory phase) is fairly constant (12–14 days).

The length of the menstrual cycle refers to the time interval between the first day of the period and the first day of the subsequent period. This may vary from 21 to 35 days in normal women, but menstruation usually occurs every 28 days.

It is important to note the method of contraception prior to conception, as hormonal contraception may be associated with a delay in ovulation in the first cycle after discontinuation. The age of onset of menstruation (the menarche) may be relevant in teenage pregnancies to determine the onset of fertility.

The estimated date of delivery (EDD) can be calculated from the first day of the last menstrual period by adding 9 months and 7 days to this date. However, to apply this Naegele’s rule, the first day of the menstrual period should be accurate and the woman should have had regular 28-day menstrual cycles (Fig. 6.1). The average duration of human gestation is 269 days from the date of conception. Therefore, in a woman with a 28-day cycle, this is 283 days from the first day of the last menstrual period (14 days are added for the period between menstruation and conception). In a 28-day cycle, the estimated date of delivery can be calculated by subtracting 3 months from the first day of the LMP and adding on 7 days (or alternatively, adding 9 months and 7 days). It is important to appreciate that only 40% of women will deliver within 5 days of the EDD and about two-thirds of women deliver within 10 days of EDD. The calculation of EDD based on a woman’s LMP is therefore, at best, a guide to a woman as to the date around which her delivery is likely to occur.

If a woman’s normal menstrual cycle is less than 28 days or is greater than 28 days, then an appropriate number of days should be subtracted from or added to the estimated date of delivery. For example, if the normal cycle is 35 days, 7 days should be added to the estimated date of delivery.

Previous obstetric history

The term ‘gravidity’ refers to the number of times a woman has been pregnant, irrespective of the outcome of the pregnancy, i.e. termination, miscarriage or ectopic pregnancy. A primigravida is a woman who is pregnant for the first time and a multigravida is a woman who has been pregnant on two or more occasions.

This term ‘gravidity’ must be distinguished from the term ‘parity’, which describes the number of live-born children and stillbirths a woman has delivered after 24 weeks or with a birth weight of 500 g. Thus, a primipara is a woman who has given birth to one infant after 24 weeks.

A multiparous woman is one who has given birth to two or more infants, whereas, a nulliparous woman has not given birth after 24 weeks. The term ‘grand multipara’ has been used to describe a woman who has given birth to five or more infants.

Thus, a pregnant woman who has given birth to three viable singleton pregnancies and has also had two miscarriages would be described as gravida 5 para 3: multigravid multiparous woman.

A parturient is a woman in labour and a puerpera is a woman who has given birth to a child during the preceding 42 days.

A record should be made of all previous pregnancies, including previous miscarriages, and the duration of gestation in each pregnancy. In particular, it is important to note any previous antenatal complications, details of induction of labour, the duration of labour, the presentation and the method of delivery as well as the birth weight and sex of each infant.

The condition of each infant at birth and the need for care in a special care baby unit should be noted. Similarly, details of complications during labour as well as puerperium such as postpartum haemorrhage, infections of the genital tract and urinary tract, deep vein thrombosis (DVT) and perineal trauma should be enquired. It is vital to appreciate that these complications may have a recurrence risk and also may influence the management of subsequent pregnancies, e.g. history of DVT requires thromboprophylaxis during the antenatal as well as postnatal periods.

Family history

Most women will be aware of any significant family history of the common genetically based diseases and it is not necessary to list all the possibilities to the mother as it may increase her anxiety. A general enquiry as to whether there are any known inherited conditions in the family will be sufficient, unless one partner (or both) is adopted and not aware of their family history.

Detailed and relevant information obtained with regard to demographics (e.g. maternal age, increased BMI), past obstetric, medical and surgical (e.g. laparotomy, caesarean section, myomectomy) history and family history will help perform appropriate tests as well to make a care plan.

General and systemic examination

At the initial visit to the clinic, i.e. the booking visit, a complete physical examination should be performed to identify any physical problems that may be relevant to the antenatal care.

Height and weight are recorded at the first and all subsequent visits and this will help calculation of Body Mass Index (BMI = weight in kg/height in m²).

   Measuring blood pressure in pregnancy

Blood pressure is recorded with the patient supine and in the left lateral supine position to avoid compression of the inferior vena cava by the gravid uterus (Fig. 6.2). If blood pressure is to be recorded in the sitting position, then it should be recorded in the same position for all visits and on the same arm. The effect of posture on blood pressure has been noted in Chapter 3. Vena caval compression in late pregnancy may cause symptoms of syncope and nausea and this is associated with postural hypotension, the condition being known as the supine hypotensive syndrome. If this is not recognized for a prolonged period, fetal compromise may occur secondary to a reduction in uteroplacental circulation.

Although in the past the diastolic pressure has always been taken as Korotkoff fourth sound, where the sound begins to fade, it is now agreed that where the fifth sound, i.e. the point at which the sound disappears, is clear, this should be used as representing the diastolic pressure. If the point at which the sound disappears cannot be identified because it continues towards zero, then the fourth sound should be used.

Heart and lungs

A careful examination of the heart should be made to identify any cardiac murmurs. Benign ‘flow murmurs’ due to the hyperdynamic circulation associated with normal pregnancy are common and are of no significance. These are generally soft systolic bruits heard over the apex of the heart, and occasionally a mammary souffle is heard, arising from the internal mammary vessels and audible in the second intercostal spaces. This will disappear with pressure from the stethoscope (Fig. 6.3).

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