Antenatal Care and Complications

Anaemia

The normal range is 12-16g/dL (Non-pregnant), or 10.5-13g/dL (Pregnant). This drop in Hb during pregancy is due to a normal increase in plasma volume and red cell mass, therefore leading to haemodilution (lower Hb concentration).

Anaemia during pregnancy is also commonly caused by Iron deficiency. Other much less common causes include Vitamin B12/Folate deficiency, Sickle cell/Thalassaemia, and Blood disorders.

If B12 (Cobalmin) deficient, IF antibodies can be tested for to diagnose Pernicious anaemia. This is treated with Hydroxocobalamin or Cyanocobalamin.

Pre-existing Diabetes

An ↑HbA1c during pregnancy is associated with Congenital malformations, including Sacral agenesis, Skeletal and Neural Tube Defects, and Congenital heart disease.

Maternal hyperglycaemia causes B-cell Hyperplasia, therefore leading to foetal hyperinsulinaemia. This in turns leads to Macrosomia, which can cause a complications of labour dystocia and birth injuries. Shortly after birth, there's a huge risk of neonatal hypoglycaemia, due to the sustained high foetal insulin levels. This can present with seizures.

Management includes:

• Better pre-gestational diabetic control

• Ultrasound – Detect congenital abnormalities and assess foetal growth

• Timing of delivery - Evaluating risk between Intrauterine death and Respiratory distress, as well as between Macrosomia, Shoulder dystocia and Caesarean delivery

• Retinopathy Screening – Very important to screen for this during pregnancy!

• Screening for Pre-eclampsia

Gestational Diabetes (GDM)

GDM is DM that's diagnosed for the first time after 20 weeks gestation. During pregnancy, placental steroids (hPL, cortisol, oestradiol, glucagon) lead to insulin resistance, which increases glucose for placental transfer.

Risk factors - Obesity, Family Hx, Previous hx of macrosomia, PCOS, Older age

Investigations:

• Screen high-risk groups at Booking, Screen everyone at 28 weeks

• OGTT - Diagnosed if fasting > 5.6 and/or 2hr glucose > 7.8

N.B. Remember the diagnostic criteria of GDM by 5678! - 5.6mmol/L fasting, 7.8mmol/L 2 hr plasma glucose.

N.B. All patients with a risk factor for GDM should be offered an OGTT at 24-28 weeks.

Management:

• Fasting glucose < 7 - trial of diet and exercise for 1-2 weeks, followed by metformin, then insulin

• Fasting glucose > 7 - start insulin ± metformin

• Fasting glucose > 6 plus macrosomia (or other complications) - start insulin ± metformin

N.B. These patients shouldn’t give birth any later than 40+6 weeks.

Pre-existing Hypertension

ACEi's and ARB's must be stopped during pregnancy as they both affect the RAAS, therefore affecting foetal kidneys and their production of urine → Oligohydramnios – Hypocalvaria (incomplete formation of the skull bones).

Safer options to use during pregnancy are Labetalol (1st line), Nifedipine, or Methyldopa.

Pregnancy-induced Hypertension

This is HTN after 20 wks w/o proteinuria (differentiating feature from PET). The severe form of this is Pre-eclampsia, where there’s end-organ damage and proteinuria.

Complications - Pre-eclampsia, Eclampsia, Stroke, Placental abruption, Intrauterine Growth Restriction, Stillbirth, Preterm delivery (induced if foetal distress)

Management:

• Labetalol, Nifedipine, or Methyldopa

• BP monitoring, and looking out for symptoms of any complications e.g. with regular urine dips, screens, and check-ups

UTI

The most common cause of in pregnancy is E.coli.

Management - 7-day course of

• Nitrofurantoin 100mg BD - Avoid in 3rd trimester/at term - 1st line

• Amoxicillin/Cefalexin – 2nd line

Trimethoprim should be avoided in the 1st trimester as it’s a folate antagonist, therefore avoided as folate is very important for normal foetal development – Can cause congenital malformations if deficient (particularly NTDs).

Epilepsy

This is a concern during pregnancy as:

• The physiological changes during pregnancy can lower the seizure threshold and increase the frequency of them

  • Prolonged seizures can increase the risk of foetal hypoxia

• Maternal use of anti-epileptics can increase the risk of NTDs

Anti-epileptics to avoid include:

• Sodium valproate as it causes NTDs and developmental delay

• Phenytoin as it causes cleft lip and palate

Safer anti-epileptic options are Levetiracetam and Lamotrigine.

Substance-use

Alcohol-use during pregnancy can lead to miscarriage, stillbirth, birth defects, and foetal alcohol syndrome (FAS).

Opioid-use during pregnancy can lead to poor foetal growth, premature delivery, stillbirth, birth defects, and neonatal abstinence syndrome (NAS). NAS is where the baby experiences withdrawal symptoms (irritability, tachypnoea, fever, poor feeding) after birth.

Tobacco-use during pregnancy can lead to premature delivery, low birth weight, cleft lip and palate, and sudden infant death syndrome (SIDS).