Fibroid in Pregnancy

Fibroid in pregnancy is the presence of uterine fibroids during gestation, found in a minority of pregnancies. Most fibroids do not change size or cause problems.

• Fibroids may grow in the first trimester, then stop or shrink.
• Large (above 5 cm), retroplacental, or submucosal fibroids raise the risk of complications.
• Management is mainly expectant, with a delivery plan.

Usually none; others have pelvic pain, vaginal bleeding or a uterus larger than dates.

• A firm, irregular uterus; malpresentation or high presenting part.
• Differential diagnosis: ovarian mass, uterine contraction, placental abruption, placenta praevia, adenomyosis, multiple pregnancy, polyhydramnios.
• Complications: red degeneration, miscarriage, abruption, preterm labour, malpresentation, fetal growth restriction, obstructed labour, caesarean delivery and postpartum haemorrhage.

Diagnosis is by early ultrasound that records the size, number and position of the fibroids.

• Early ultrasound documenting size, number, position and relation to the placenta and cervix.
• Growth scans every 4 weeks from 28 weeks if the fibroid is large or the fetus is small.
• Full blood count and ferritin; blood group and antibody screen.
• MRI without gadolinium if the findings are unclear.
• Placental site on ultrasound at 20 weeks.

Manage expectantly with a delivery plan, and treat pain and anaemia.

• Supportive: routine antenatal care with extra visits for large fibroids; explain pain patterns; plan delivery in a facility with blood and surgical ability.
• Pharmacological: paracetamol 1 g oral 6-hourly (maximum 4 g in 24 hours) for pain; avoid ibuprofen from 28 weeks; morphine 2.5 to 5 mg IV for severe pain. Anaemia: ferrous sulphate 200 mg oral 8-hourly; iron sucrose 200 mg IV per dose in the second or third trimester for severe anaemia. Give folic acid 400 micrograms oral daily in early pregnancy. Prevent postpartum haemorrhage: oxytocin 10 IU IM after delivery of the baby; carbetocin 100 micrograms IV slowly over 1 minute; tranexamic acid 1 g IV over 10 minutes for bleeding. Preterm labour risk: dexamethasone 6 mg IM 12-hourly for 4 doses between 24 and 34 weeks.
• Procedures: avoid myomectomy in pregnancy, except for torsion of a pedunculated fibroid or necrosis. Do not remove fibroids at caesarean delivery unless they are pedunculated or bleed and the surgeon is experienced. Plan caesarean delivery for fibroids that block the lower segment or for malpresentation.
• Special groups: in women with a previous myomectomy that opened the cavity, plan caesarean delivery at 37 to 38 weeks.
• Red flags: severe pain with fever, vaginal bleeding, regular contractions, reduced fetal movements.
• Follow-up: postnatal review at 6 weeks, ultrasound of the fibroid at 3 months, contraception counselling.