Medical conditions in pregnancy

Question 1

What is the impact of pregnancy on pre-existing diabetes

Answer 1

Diabetes generally worsens during pregnancy
- Increased insulin resistance and a relative glucose intolerance → increased insulin requirements, especially in the third trimester
- Increased risk of hypoglycaemia + unawareness due to similarity of symptoms
- Risk of diabetic nephropathy and retinopathy deterioration

Question 2

What are the risks of pre-existing diabetes mellitus on pregnancy

Answer 2

Miscarriage
Pre-eclampsia
Infections e.g. UTI
Delivery by LSCS
Congenital abnormalities (especially cardiac)
Stillbirth
Neonatal RDS
Neonatal hypoglycaemia (oversecretion of insulin from the foetal pancreas)
Macrosomia and resultant delivery risks e.g. shoulder dystocia
IUGR
Polyhydramnios

Question 3

What is the antenatal care for pre-existing diabetes in pregnancy

Answer 3

Good diabetic control pre-conception, reduces risk of congenital abnormalities and miscarriage
Intense capillary blood glucose (CBG) monitoring - 4x a day fasting (aim <5.4) + 1 hour post meals BM (aim <7.8)
Eye screen at booking and repeated 2nd trimester
Review every 1-2 weeks in a joint obstetric diabetes clinic
Regular growth scans every 4 weeks from 28 weeks (look for cardiac abnormality at anomaly USS)
Aspirin 75-150mg from 12-36w
Insulin and metformin are safe to take during pregnancy, all other oral hypoglycaemic drugs should be stopped

Question 4

What is the intrapartum and postpartum care for pre-existing diabetes in pregnancy

Answer 4

Intrapartum
IOL at 37-38 weeks
Consider ELCS if large baby

Postnatal
Immediately revert to pre-pregnancy dosing
Follow up at diabetic clinic
Continue metformin and insulin during breastfeeding.

Question 5

What is the impact of pregnancy on asthma

Answer 5

Unpredictable - may improve, deteriorate or remain unchanged
- Most likely to deteriorate if poorly controlled at conception
- Exacerbations are uncommon in labour - increased exogenous steroids
- New diagnosis in pregnancy is usually seen at around 34 weeks

Question 6

What is the antenatal care for asthma in pregnancy

Answer 6

Stay on asthma medication in pregnancy (all meds safe)
Step-wise approach to treatment is the same (including severe asthma)
Frequency of review depends on severity and control of disease (every 2-8 weeks by the obstetrician ± respiratory)
Re-consider any aspirin use
If on PO steroids, will need GTT

Question 7

What is the intrapartum and postpartum care for asthma

Answer 7

Intrapartum
No impact to analgesia or mode of delivery
Avoid carbopost for PPH management

Postnatal
Asthma may improve if it had deteriorated in pregnancy
Follow up with GP or in asthma clinic
Medications are all safe in breastfeeding

Question 8

What is the impact of pregnancy on epilepsy

Answer 8

Generally stays the same
Increased risk of SUDEP
1/3 will have increased seizure frequency in pregnancy:
- Non-compliance with medications
- There are reduced free epilepsy drug levels - would need to increase the dose (increased plasma volume, enhanced renal/hepatic clearance, reduce absorption
- Some epilepsy medications are contraindicated
- Increased risk of seizures due to pain, stress, lack of sleep

Question 9

What are the risks of epilepsy in pregnancy

Answer 9

Miscarriage
IUGR
Congenital abnormalities (cardiac, neural tube defects): Increased risk to those not on AEDs (anti-epileptic drugs)
Epilepsy in the offspring: 4-5% in either parent has epilepsy, both parents 15-20%

Question 10

Describe the use of anti-epileptics in pregnancy

Answer 10

Levetiracetam and lamotrigine used
Epileptic medications can be teratogenic as they cross the placenta e.g. valproate, phenytoin, carbamazepine, lamotrigine, topiramate, levetiracetam - can cause cleft palate, cardiac issues or spina bifida
These medications do not have an effect on fertility
Should balance the risks and benefits - it is safer to have controlled epilepsy than uncontrolled off medications

Question 11

What is the management for epilepsy in pregnancy

Answer 11

Antenatal
Folic acid 5mg OD from 3 months prior to conception until 12 weeks
Switch from valproate to another AED
Advise to stay on AEDs in pregnancy
Join management in specialist ANC
Anomaly scan at 20w with fetal echo
Serial growth scans

Intrapartum: consider early epidural (prevent triggers e.g. lack of sleep, pain)
Postnatal: can breastfeed with AEDs

Question 12

What are the causes of hypothyroidism

Answer 12

Goitre: Hashimoto’s (most common), iodine deficiency
No goitre: iatrogenic, atrophic thyroiditis, congenital developmental defect
Drugs: iodine, lithium, amiodarone, anti-thyroid
Pituitary: hypopituitarism, isolated TSH deficiency
Hypothalamic: neoplasm, sarcoidosis, encephalitis/infection

Question 13

What is the impact of pregnancy on pre-existing hypothyroidism

Answer 13

Usually no effect
Some may need to increase thyroxine dose due to inadequate treatment prior to pregnancy (25mcg+)

Question 14

What are the risks of hypothyroidism in pregnancy

Answer 14

(if untreated, otherwise good outcomes)

Infertility
Miscarriage
Anaemia
PET
Low birthweight babies
Hypothyroxinaemia in early pregnancy → delayed mental and motor function
Neonatal/foetal hypothyroidism (cretinism) due to transplacental transfer of TSH receptor antibodies (Foetal thyroid cannot produce thyroxine until week 12 so relies on maternal thyroxine)

Question 15

What is the management for hypothyroidism in pregnancy

Answer 15

Antenatal:
Optimise control pre-pregnancy
Continue the same dose of thyroxine in pregnancy with adjustments guided by pregnancy-specific TFTs
Regular TFTs, 1 per trimester
Starting dose for newly diagnosed hypothyroidism (50mcg)

Postpartum: Guthrie spot for foetal hypothyroidism

Question 16

What are the causes of hyperthyroidism

Answer 16

TSH driven: Graves (most common), GTD, TSH-oma
Autonomous T4 secretion: toxic nodule
Destruction of the thyroid: thyroiditis
Other: lithium, amiodarone, cancer mets, iodine

Question 17

What is the impact of pregnancy on hyperthyroidism

Answer 17

Can worsen in the first trimester
Often improves throughout the pregnancy, especially 2nd and 3rd trimesters
Exacerbation may occur postnatally

Question 18

What are the risks fo hyperthyroidism in pregnancy

Answer 18

Miscarriage
IUGR (increased metabolism)
Preterm labour
Placental abruption
PIH/PET
Stillbirth
AF
Cardiac failure
Thyroid storm/foetal thyrotoxicosis
Foetal hyperthyroidism (tachycardia, hydrops, FGR, goitre, accelerated bone maturation)

Question 19

What is the management for hyperthyroidism in pregnancy

Answer 19

Antepartum
Check TSH and fT4/T3 every 4 weeks
Check TSH-R antibodies in all women with history of graves
Foetal neck scan for goitre at 20-24 weeks
Serial growth scans
Antithyroid drugs: carbimazole and PTU
Beta blockers (propranolol 40mg)
Thyroidectomy, usually in the second trimester in those with dysphagia, stridor or allergies to both anti-thryoid drugs

Postpartum: Avoid pregnancy for at least 6 months after treatment completion

Question 20

What are the side effects of anti-thyroid medication in pregnancy

Answer 20

PTU: 1 in 1000 risk of acute liver failure, agranulocytosis
Carbimazole: agranulocytosis, risk of aplasia cutis an choanal atresia

Question 21

What is post-partum thyroiditis

Answer 21

The immune system attacks the thyroid within around 6 months of giving birth.
This causes a temporary rise in thyroid hormone levels and symptoms of hyperthyroidism.
In most women, thyroid function returns to normal within 12 months of childbirth.
Three stages
1. Thyrotoxicosis
2. Hypothyroidism
3. Normal thyroid function (but high recurrence rate in future pregnancies)

Question 22

What is the management for postpartum thyroiditis

Answer 22

thyrotoxic phase
- propranolol is typically used for symptom control
- not usually treated with anti-thyroid drugs as the thyroid is not overactive.

hypothyroid phase
- usually treated with thyroxine