A baby was born at 32 weeks with a birth weight of 1.59 kg. Mother had complex medical history including diabetes mellitus, chronic hypertension, nephropathy, maculopathy, ischaemic stroke on aspirin, hyperthyroidism and polycystic ovarian syndrome. Antenatal scan showed ambiguous genitalia with clitoromegaly and mother had bilateral adnexal multi-separated cysts. Baby was born by emergency lower segment cesaerean section due to pre-clampsia and biopsy of mother adnexal mass was performed. On examination, baby had clitoromegaly 0.9 cm×0.6 cm and prominent labial minora. Anogenital distance 0.9 cm. No gonads palpable, labial fusion, rugae, nor hyperpigmentation. Anus was patent and other systemic review unremarkable. Urgent karyotype confirmed 46XX. Electrolytes, glucose and newborn screening were normal. Hormonal profile showed normal 17a-OH progesterone (17OHP). Testosterone (TA) ↑4.6 nmol/l. DHEAS was slightly elevated. Ultrasound pelvis showed uterus,cervix and normal bilateral adrenal glands. Mother was also virilised with clitoromegaly and hirsutism over chin, thigh and pubic region. During pregnancy, TA ↑27 nmol/l, DHEAS normal, sex hormone binding globulin (SHBG) >180 nmol/l. In view of maternal virilisation with ↑TA, ↑SHBG but normal DHEAS and bilateral maternal adnexal mass, baby virilization could be due to pregnancy luteoma or hyperrectio luteinalis (HL) or rarely androgen secreting ovarian tumor. On the other hand, babys condition like P450 oxidoreductase deficiency could cause both baby and maternal virilization but this could not explain maternal bilateral adnexal mass and baby also did not have any skeletal features. Other differential diagnosis such as congenital adrenal hyperplasia (CAH) is less likely as this could not explain maternal features. Histology of mother adnexal mass came back to be corpus luteal cyst of pregnancy. Further discussion with pathologist confirmed it was more compatible with hyperrectio luteinalis. Hence we monitored baby and her mothers blood serially. Baby DHEAS gradually normalized and her TA dropped to 2.1 nmol/l in 1 month and gradually normalised. Mothers TA also fell from 29 nmol/l post-partum to 0.54 nmol/l in 1 month then gradually normalised. HL is a benign, pregnancy related cystic enlargement of the ovaries. Most (66%) occurred in primiparity. Comorbidities include PCOS and thyroid problem. Most had elevated androgen (84%). 30% had maternal virilization and rarely 3.5% had fetal virilization because of the timing of androgen exposure and protective mechanisms such as ↑maternal SHBG, progesterone competing for androgen binding sites, conversion of maternal androgen to estrogen. Nevertheless, HL will resolve after baby delivery and hence warrant a conservative approach.