Chronic Conditions in Pregnancy

Women with existing health conditions may need additional management of both the existing health condition and the pregnancy. They are generally managed jointly by the obstetric team and the specialist in their health condition.


Hypothyroidism in Pregnancy

Untreated or under-treated hypothyroidism in pregnancy can lead to several adverse pregnancy outcomes, including miscarriage, anaemia, small for gestational age and pre-eclampsia.

Hypothyroidism is treated with levothyroxine (T4). Levothyroxine can cross the placenta and provide thyroid hormone to the developing fetus. The levothyroxine dose needs to be increased during pregnancy, usually by at least 25 – 50 mcg (30 – 50%). Treatment is titrated based on the TSH level, aiming for a low-normal TSH level.



Women with existing hypertension may need changes to their medications.

Medications that should be stopped as they may cause congenital abnormalities:

  • ACE inhibitors (e.g. ramipril)
  • Angiotensin receptor blockers (e.g. losartan)
  • Thiazide and thiazide-like diuretics (e.g. indapamide)


Medications that are not known to be harmful:

  • Labetalol (a beta-blocker – although other beta-blockers may have adverse effects)
  • Calcium channel blockers (e.g. nifedipine)
  • Alpha-blockers (e.g. doxazosin)


Epilepsy in Pregnancy

Women with epilepsy should take folic acid 5mg daily from before conception to reduce the risk of neural tube defects.

Pregnancy may worsen seizure control due to the additional stress, lack of sleep, hormonal changes and altered medication regimes. Seizures are not known to be harmful to the pregnancy, other than the risk of physical injury.

Ideally, epilepsy should be controlled with a single anti-epileptic drug before becoming pregnant.

Regarding anti-epileptic drugs:

  • Levetiracetamlamotrigine and carbamazepine are the safer anti-epileptic medication in pregnancy
  • Sodium valproate is avoided as it causes neural tube defects and developmental delay
  • Phenytoin is avoided as it causes cleft lip and palate


There are a lot of warnings about the teratogenic effects of sodium valproate, and NICE updated their guidelines in 2018 to reflect this. It must be avoided in girls or women unless there are no suitable alternatives and strict criteria are met to ensure they do not get pregnant. There is a specific program for this, called Prevent (valproate pregnancy prevention programme).


Rheumatoid Arthritis

Rheumatoid arthritis is an autoimmune condition that causes chronic inflammation of the synovial lining of the joints, tendon sheaths and bursa. It is an inflammatory arthritis. It is treated with disease-modifying anti-rheumatic drugs (DMARDs).

Ideally, rheumatoid arthritis should be well controlled for at least three months before becoming pregnant. Often the symptoms of rheumatoid arthritis will improve during pregnancy, and may flare up after delivery.

The treatment regime may need to be altered by a specialist rheumatologist before and during pregnancy:

  • Methotrexate is contraindicated, and is teratogenic, causing miscarriage and congenital abnormalities
  • Hydroxychloroquine is considered safe during pregnancy and is often the first-line choice
  • Sulfasalazine is considered safe during pregnancy
  • Corticosteroids may be used during flare-ups


Last updated September 2020