Updated Role of Ultrasound for Predicting Pregnancy Outcome in First-Trimester Vaginal Bleeding

Abstract

Backgrounds: Vaginal bleeding during the first trimester is a common obstetric condition.  Approximately 20-25% women in their first trimester complain of vaginal bleeding   The vast variety of reasons of early pregnancy bleeding, the risk of miscarriage, and the worry of having any life threatening etiology puts pregnant women with first trimester hemorrhage in a state of uncertainty, leading to anxiety .

Aim:  To predict pregnancy outcome through sonographic findings of subchorionic hematoma, slow fetal heart rate and high resistance to subtrophoblastic  circulation  in women presenting with vaginal bleeding  in first trimester

Patients &Methods: A prospective study was conducted during twenty- month   period from September 2021 to April 2023 on 60 pregnant patients during 6-13+6dweeks of gestation with positive pregnancy test ,complaining of vaginal bleeding. The study group was subdivided into group of non-viable pregnancy ( 16 cases) and threatened abortion group(44 cases).  The   group of threatened abortion was subdivided into group of patients who ended  in second trimester miscarriage (6 patients) and termination of pregnancy  (2 patients) and a group who continued pregnancy (36 patients). Pregnancies were followed up until the final outcome was known .  Confirmation of completed pregnancy loss was done with examination of   the abortus products that passed spontaneously or after uterine aspiration for non viable group  .Antenatal  and neonatal outcomes were obtained from hospital records for cases of threatened abortion continued pregnancy to labor  . The relation between slow embryonic (fetal) heart rate , subchorionic hematoma and high resistance to subtrophoblastic circulation  and fetal demise was recorded and statistically analyzed.

Results: Spotting was most common nature of bleeding per vagina 63.3% (38/60). .Among 60 subjects who were included in the study, 44 patients (73.3%) were diagnosed by US as viable pregnancy and  16 patients ( 26.7%) were non-viable pregnancy  . Among 44 cases of viable pregnancy in the first trimester, 6 (10.0%) ended in second trimester miscarriage  , 2(3.3%) were subjected to pregnancy termination (aneuploidy ) and 36 (60%) completed their pregnancies of which the live birth rate   was 81.8% of which 28 patients had no  perinatal complications, and others (22.2%) had problems of PROM, and preterm labor . The prevalence of subchorionic hematoma  in threatened abortion group was 22.7% (n = 10) and there was   association between the size of the  subchorionic hematoma and first trimester miscarriage. There was a statistically significant differences in pregnancy outcomes between those with and without subchorionic hematoma .There is highly significant relation between incidence of abortion and the slowing FHR and high resistance to subtrophoblastic circulation where p-value <0.001 and    respectively

Conclusions: 

 First trimester bleeding could be a predicting factor for perinatal complications .Slow embryonic (or fetal)  heart rate as well as increased resistance to subtrophoblastic circulation  could be  the earliest  predictors for subsequent possible miscarriage.Large subchorionic hematoma may increase  the risk of miscarriage in patients with vaginal bleeding and so early follow up by ultra sound is recommended a and this help the clinician to make the diagnosis of fetal demise quickly.