Unicornuate Uterus and Pregnancy Outcome
Southern gems hospital, palace colony road, hill fort, adarsh nagar, hyderabad, telangana, india, Bengaluru Oct 21, 2019
Congenital Uterine Anomalies
Congenital uterine anomalies result from an abnormal formation, fusion or reabsorption of Mullerian ducts during fetal life. These anomalies are present in 1 to 10% of the unselected population, 2 to 8% of infertile women and 5 to 30% of women with a history of miscarriages.
The European Society of Human Reproduction and Embryology—European Society for Gynecological Endoscopy (ESHRE-ESGE) recognizes two types of unicornuate uterus: 1) hemi-uterus with a rudimentary functional contralateral cavity, communicating or non-communicating, due to a partial Mullerian duct development (class IVa), and 2) isolated Hemi-uterus caused by a unilateral agenesis of Mullerian duct (class IVb).
Ovarian development usually is not compromised although ovary on the affected side may be misplaced higher in the abdomen or even absent in rare cases. Coincidental renal anomalies are common, and there is an increased risk of developing endometriosis or chronic pain due to hematometra in women with a rudimentary horn.
The presence of a maternal uterine anomaly is associated with an increased risk of recurrent first and mid-trimester loss, preterm birth, fetal malpresentation, cesarean section, placenta previa, placental abruption and Intrauterine Growth Retardation (IUGR).' The possible causative factors include reduced uterine muscle mass, aberrant uterine vasculature and smaller size of the uterine cavity. It has been proposed that derangements in endometrial vascularization with deleterious effect on endometrial receptivity and implantation could play a role.”
As pregnancy in the unicornuate uterus is associated with several obstetric complications, careful monitoring throughout pregnancy is essential to identify these problems so that preventive measures can be taken.
- Mrs SM, a 29-year-old woman, had consulted our centre. She has been married for 3-1/2 years.
- Her menstrual cycles have been irregular (once in 60-90 days) since she attained menarche, with normal flow and no dysmenorrhea
- She has a history of primary infertility of 2-year duration © She is a known hypothyroid and on regular medication, levothyroxine 25 mcg per day
- An ultrasound evaluation via a three-dimensional (3D) ultrasound was performed. The investigation revealed a left unicornuate uterus with dimensions of 75] x? 302 x229 mm with an endometrial thickness according to her menstrual phase. At the right side, lining her right ovary, a non- communicating rudimentary horn was described.
- She underwent hysteroscopy, and an expansion metroplasty was performed
- Her investigations revealed D2 Follicle-stimulating Hormone (FSH) (5.82 mlU/mL), Luteinizing Hormone (LH) (2.5 mlU/mL), serum prolactin (8.3 ng/mL), Thyroid-stimulating Hormone (TSH) (1.31) and Anti-Mullerian Hormone (AMH) (2.2 ng/mL)
- Her husband is a 31-year-old non-smoker who takes alcohol socially, otherwise healthy. The husband's semen analysis revealed a sperm count of 1 million, sperm motility of 25% actively motile sperm and morphology of 2% normal forms.
The couple was counselled about their status; they were explained that as the semen count was very low, Intracytoplasmic Sperm Injection (ICSI) was recommended. The couple agreed to proceed with the process. She underwent ICSI in antagonist protocol, 8 eggs collected and for 5 mature eggs ICSI was done. She had a single blastocyst which was transferred on day 5. Subsequently 2 weeks later, she was pregnant with a beta Human Chorionic Gonadotropin (HCG) of 355.75 mIU/mL.
Throughout the pregnancy, she had routine blood tests, and ultrasound examinations were regularly performed.
- She had an ultrasound at 12 weeks, which revealed a cervical length of 32 mm, and the patient was counselled that there was no increase of mid-trimester loss and preterm delivery. Hence, a cervical cerclage was not performed. She was continued on progesterone supplementation with micronized progesterone 200 mg twice a day until delivery.
- Obstetric ultrasound examinations at the first, second and third trimester of her pregnancy showed a normal anterior fundal placenta, normal amniotic fluid index and breech presentation
- From 28 weeks of pregnancy onwards, serial growth scans were performed, which confirmed a normal growth
- At 37 weeks of pregnancy, the patient presented to the hospital complaining of contractions and light vaginal bleeding. Cardiotocography and ultrasound measurement of her cervix was immediately performed. On her pelvic examination, the cervix was closed; cardiotocography revealed uterine contractions and her cervix length was 28 mm on ultrasound examination.
- She underwent a cesarean section, and she had a healthy baby with an Apgar score of 9 and 10, a weight of 2305 g and a length of 49 cm
- The mother had no post-surgery complications
Cervical cerclage is the best treatment for women with a short cervix (<25 mm), and particularly for women with a history of prior mid-trimester pregnancy losses due to cervical insufficiency.’ As there is increased risk of mid-trimester loss, several studies have suggested a benefit of placement of prophylactic cervical cerclage in all antenatal patients with a unicornuate uterus, but the Royal College of Obstetricians and Gynecologists (RCOG) guidelines advise against it (level B recommendations).*
The myometrial activity associated with preterm labour results primarily from a release of the inhibitory effects of pregnancy on the myometrium rather than an active process mediated through the release of uterine stimulants and progesterone appears to play a central role. Recent data suggest that progesterone may be important in maintaining uterine quiescence in the later half of pregnancy by limiting the production of stimulatory prostaglandins and inhibiting the expression of contraction- associated protein genes (ion channels, oxytocin and prostaglandin receptors, and gap junctions) within the myometrium. '
According to the current guidelines of the American Congress of Obstetricians and Gynecologists (ACOG) for the management of IUGR, it is reasonable to consider serial growth ultrasound examinations in pregnancies at risk of IUGR as in the case of a unicornuate uterus pregnancy.’ Therefore, serial ultrasounds from 28 weeks of gestation can be done to identify any cases of IUGR.