A Rare Association of Unicornuate Uterus and Hypothyroidism Presenting as Threatened Abortion at 16 Weeks Gestation

Threatened abortion is characterised by vaginal bleeding before 20 weeks of gestation in the presence of a closed cervix and a viable intrauterine pregnancy. The coexistence of a congenital uterine anomaly and maternal hypothyroidism may complicate clinical assessment and antenatal management. This case report describes a 31-year-old gravida 2 woman at 16 weeks and 2 days of gestation who presented with scant vaginal spotting and mild lower abdominal discomfort. She had a previously diagnosed unicornuate uterus and was receiving levothyroxine 25 µg once daily for hypothyroidism. On admission, she was haemodynamically stable, with a haemoglobin level of 11.8 g/dL and a thyroid-stimulating hormone level of 2.45 mIU/L. Ultrasonography demonstrated a single live intrauterine fetus corresponding to gestational age, normal amniotic fluid volume, a fundoposterior placenta, a cervical length of 32.9 mm, and no cervical dilatation. Conservative management included oral dydrogesterone for progesterone support, continuation of levothyroxine therapy, relative bed rest, restriction of strenuous activity, counselling, and close maternal and fetal surveillance. Vaginal spotting decreased within 48 hours and subsequently subsided, while abdominal discomfort resolved. Follow-up confirmed continued fetal viability and maternal stability. This case demonstrates a favourable short-term pregnancy course despite the simultaneous presence of threatened abortion, a unicornuate uterus, and treated hypothyroidism, while underscoring the importance of individualised surveillance in such high-risk pregnancies.