It is important to differentiate physiological abdominal pain from pathological causes in women with severe, atypical or recurrent pain. These include:

• early pregnancy problems such as ectopic pregnancy and miscarriage

• gynaecological causes such as ovarian torsion

• urinary tract infection

• surgical causes such as appendicitis and pancreatitis

• later obstetric causes such as placental abruption and labour.

Social causes, particularly domestic abuse, should be considered in women who present with recurrent episodes of abdominal pain where organic pathology has been excluded.

Once a pathological cause has been excluded reassurance is often a successful management option and analgesics are rarely required.

Heartburn

Gastro-oesophageal reflux is more likely to occur in pregnancy because of delayed gastric emptying, reduced lower oesophageal sphincter pressure and raised intragastric pressure. It affects up to 80 % of pregnant women, particularly in the third trimester. The differential diagnoses are:

• other causes of chest pain such as angina, myocardial infarction and muscular pain

• causes of upper abdominal pain that can mimic reflux, for example, pre-eclampsia, acute fatty liver of pregnancy and gallstones.

Conservative management includes dietary advice to avoid spicy and acidic foods and to avoid eating just prior to bed. Symptoms can be improved by changing sleeping position to a more upright posture. If conservative measures are not successful antacids are safe in pregnancy and can be used at any time. Histamine-receptor blockers, such as ranitidine, and proton pump inhibitors have a good safety profile in pregnancy and can be used if antacids alone are insufficient to improve symptoms.

Medical problems arising in pregnancy

Anaemia

Anaemia commonly occurs in pregnancy. While in many developed countries it is mild and quickly and easily treated resulting in minimal complications, in some countries it is severe and a major contributor to maternal death.

Aetiology

Pregnancy causes many changes in the haematological system, including an increase in both plasma volume and red cell mass; the former is greater than the latter with the result that a ‘physiological anaemia’ often occurs. There is an increased iron and folate demand to facilitate both the increase in red cell mass and fetal requirements, which is not always met by maternal diet. Iron deficiency anaemia is thus a common condition encountered in pregnancy, particularly in the third trimester. Table 9.1 shows the changes of haemoglobin and red cell parameters in normal pregnancy.

Table 9.1

Haemoglobin and red cell indices (mean and calculated 2.5th–97.5th percentile reference ranges)

Red cell indices	Gestation
	18 weeks	32 weeks	39 weeks	8 weeks postpartum
Haemoglobin (Hb) g/dL	11.9 (10.6–13.3)	11.9 (10.4–13.5)	12.5 (10.9–14.2)	13.3 (11.9–14.8)
Red cell count × 10¹²/L	3.93 (3.43–4.49)	3.86 (3.38–4.43)	4.05 (3.54–4.64)	4.44 (3.93–5.00)
Mean cell volume (MCV) fL	89 (83–96)	91 (85–97)	91 (84–98)	88 (82–94)
Mean cell haemoglobin (MCH) pg	30 (27–33)	30 (28–33)	30 (28–33)	30 (27–32)
Mean cell haemoglobin concentration (MCH) g/dL	34 (33–36)	34 (33–36)	34 (33–36)	34 (33–36)
Haematocrit	0.35 (0.31–0.39)	0.35 (0.31–0.40)	0.37 (0.32–0.42)	0.39 (0.35–0.44)

(Reproduced with permission from Shepard MJ, Richards VA, Berkowitz RL, et al (1982) An evaluation of two equations for predicting fetal weight by ultrasound. Am J Obstet Gynecol 142:47–54. © 1982 Elsevier.)

Risk factors

Pre-pregnancy risk factors are those associated with chronic anaemia:

• iron deficiency secondary to poor diet

• menorrhagia

• short interval between pregnancies

• presence of anaemic conditions, such as sickle cell disease, thalassaemia and haemolytic anaemia.

Risk factors within pregnancy include multiple pregnancy due to the increased iron demand in multiple pregnancy scenarios.

Clinical features and diagnosis

Anaemia is often identified as the result of routine full blood count measurements. Some women will present with symptoms such as shortness of breath and lethargy. There is a variation in normal haemoglobin levels in pregnancy and a gradual fall as pregnancy progresses. Anaemia can be diagnosed with a haemoglobin level less than 11 g/dL in the first trimester and less than 10.5 g/dL in the second and third trimesters.

Implications on pregnancy

Iron-deficiency anaemia mainly affects the mother. With mild anaemia the fetus is usually unaffected despite the reduced oxygen-carrying capacity of the mother. However the baby is more likely to have iron deficiency in the first year of life because of a lack of development of fetal iron stores in utero. With severe anaemia there is an increased risk of preterm birth and low birth weight.

The implications to the mother in all trimesters are the risk of developing symptomatic anaemia that can cause fatigue, reduced work performance and an increase in susceptibility to infections. If anaemia persists to the time of delivery, there will be a lack of reserve if significant blood loss occurs. There is a strong association between severe anaemia and maternal mortality. The risk of requiring blood transfusions peripartum is also raised.

Management

Prompt recognition and treatment of developing anaemia optimizes a woman’s haemoglobin levels in pregnancy and reduces the risk of commencing labour anaemic.

Although most anaemia in pregnancy is secondary to iron deficiency, consideration should be given as to whether there is an underlying anaemia condition or if folate deficiency could also be involved. If there is clinical suspicion that iron deficiency is not the cause of the anaemia or if a woman has failed to respond to iron supplementation then the iron status should be assessed by either ferritin or zinc protoporphyrin levels, folate measured and haemoglobin electrophoresis performed to exclude haemoglobinopathies. Oral iron supplementation is recommended as first line treatment. This is better absorbed if taken with ascorbic acid (for example, orange juice) and if tea and coffee are avoided at the time of ingestion. Dietary advice should also be given. Compliance with iron supplementation is often poor due to the side effects of constipation and gastric irritation. If iron is either not tolerated or if improvements in haemoglobin are not seen despite iron therapy then parenteral iron can be considered.

Adequate continued postnatal treatment is essential to reduce the risk of a woman entering a further pregnancy anaemic.

Prophylaxis

Routine iron supplementation throughout pregnancy may reduce the risk of iron deficiency. This is currently not a routine recommendation in the UK due to the lack of evidence of improved outcomes. In some other countries where iron deficiency is common, this is standard practice.

Gestational diabetes

Gestational diabetes is an increasingly common antenatal condition occurring in 2–9 % of all pregnancies.

Aetiology

Pregnancy induces a diabetogenic state. This is predominantly because of increased resistance to the actions of insulin due to the placental production of the anti-insulin hormones (human placental lactogen, glucagon and cortisol), though the increased production of maternal glucocorticoids and thyroid hormones during pregnancy also contribute to this. In response, the maternal pancreas must increase its production of insulin to combat this. In some women this is not achieved and gestational diabetes is the result.

Risk factors

Risk factors are the same as those for type 2 diabetes and are listed in Box 9.1. This list is taken from the NICE Clinical Guideline ‘Diabetes in pregnancy’ (2008). The Guideline only recommends that some of the risk factors should be used for screening in practice. The presence of one or more of these risk factors should lead to the offer of a75 g oral glucose tolerance test (OGTT). However, many clinicians feel that the presence of any risk factor, rather than a subset, should trigger the offer of an OGTT.

Box 9.1

Women at increased risk of glucose intolerance in pregnancy

• Previous large infant (more than 4.5 kg, or above the 95th centile for gestational age)*

• Previous gestational diabetes *

• First-degree relative with diabetes *

• Obesity (BMI more than 30 kg/m²)* or booking weight more than 100 kg

• Specific ethnic background:

– South Asian (specifically women whose country of family origin is India, Pakistan or

– Bangladesh)

– Black Caribbean

– Middle Eastern (specifically women whose country of family origin is Saudi Arabia, United Arab Emirates, Iraq, Jordan, Syria, Oman, Qatar, Kuwait, Lebanon or Egypt)

• Macrosomia in current pregnancy (variably defined in different studies, e.g., fetal abdominal circumference measured with ultrasound >90th centile, or fetal weight estimated using formulae based on ultrasound measurements)

• Glycosuria ≥1+ on more than one occasion or ≥2+ on one occasion

• Previous unexpected perinatal death

• History of polycystic ovary syndrome

• Polyhydramnios

• FBG more than 6.0 mmol/L or random blood glucose more than 7.0 mmol/L

Key: * Risk factors in bold are those that the NICE Clinical Guideline recommends should be used for screening in practice during pregnancy in the form of a 75 g oral glucose tolerance test.

(National Institutes for Health and Clinical Excellence (2008) Diabetes in pregnancy: Management of diabetes and its complications from pre-conception to the postnatal period. NICE Publication Guideline 63, p 1–38.)

Clinical features and diagnosis

Gestational diabetes may be asymptomatic. As such, a screening programme needs to be in place that can either be universal or selective. Most units prefer a selective approach for practical and financial reasons. Selective screening is offered to the at-risk groups listed in Box 9.1. As described above, screening is by an 75 g OGTT at 28 weeks, or if very high risk, early in the second trimester and then repeated at 28 weeks (if normal at the first test). In the OGTT, a fasting glucose level is first measured, then a 75 g loading dose of glucose is given and a further glucose level taken at 2 hours post-sugar load. There is an ongoing debate as to the levels of glucose at which gestational diabetes should be diagnosed. Table 9.2 indicates the two most commonly used diagnostic criteria.

Table 9.2

Diagnostic criteria for gestational diabetes using a 75g oral glucose tolerance test

Diagnostic criteria		Normal fasting value (venous plasma glucose)	Normal 2 hour value (venous plasma glucose)
WHO 1999^a	One or more abnormal values required	<7.0 mmol/L	<7.8 mmol/L
IADPSG^b	One or more abnormal values required	<5.1 mmol/L	<8.5 mmol/L

Comment: In a given population, use of the IADPSG criteria results in more diagnoses of ‘gestational diabetes’ than using the WHO criteria. WHO, World Health Organization; IADPSG, International Association of Diabetes and Pregnancy Study Groups.

^a World Health Organization: Definition, Diagnosis and Classification of Diabetes Mellitus and its Complications: Report of a WHO Consultation. Part 1: Diagnosis and Classification of Diabetes Mellitus. Geneva, World Health Organization, 1999.

^b Metzger, B.E., Gabbe, S.G., Persson, B., et al. International association of diabetes and pregnancy study groups recommendations on the diagnosis and classification of hyperglycemia in pregnancy. Diabetes Care 2010;33:676–682.

Implications on pregnancy

Gestational diabetes is predominantly a disease of the third and sometimes second trimester (Table 9.3). In the mother, the presence of gestational diabetes increases the risk of recurrent infections and of pre-eclampsia developing. For the fetus there is increased risk of polyhydramnios and macrosomia, the latter being related to the degree of glucose control. There is an increased risk of stillbirth. Considering birth, women with gestational diabetes are more likely to have an induction of labour. If vaginal birth occurs, shoulder dystocia, an instrumental birth and extended perineal tears are more common. Women with diabetes are more likely to have a caesarean section. Babies are more likely to need admission to the neonatal unit. They are at increased risk of neonatal hypoglycaemia due to the relative over-activity of the fetal pancreas in utero. This is less likely to occur if maternal blood sugars are well controlled around the time of birth. Maternal glucose readily crosses the placenta whilst insulin does not.

Table 9.3

Effect of gestational diabetes on pregnancy

	Maternal risks/complications	Fetal/neonatal risks/complications
First trimester	–	–
Second trimester Third trimester	Pre-eclampsia Recurrent infections	Macrosomia Polyhydramnios Stillbirth
Labour	Induction of labour Poor progress in labour
Delivery	Instrumental birth Traumatic delivery Caesarean section	Shoulder dystocia
Postnatal		Neonatal hypoglycaemia Neonatal unit admission Respiratory distress syndrome Jaundice
Longer term	Type 2 diabetes later in life	Obesity and diabetes in childhood and later life

Remember that glucose crosses the placenta readily and that maternal hyperglycaemia results in elevated blood glucose levels in the fetus. Insulin, on the other hand does not pass across the placenta and therefore the fetus is entirely dependent on the supply of its own insulin production for the regulation of its blood sugar levels.

Whilst for the majority of women gestational diabetes will resolve post-pregnancy, in some women this diagnosis is the unmasking of type 2 diabetes and diabetic care will need to continue. Women who have had gestational diabetes remain at higher risk of developing type 2 diabetes later in life. For the babies, fetal programming effects increase the risk of obesity and diabetes in later childhood.