First trimester vaginal bleeding is one of the most common pregnancy complications affecting 15-25% of all pregnancies. Threatened abortion is defined as bleeding through a closed cervical os in the first half of pregnancy. A subchorionic hematoma (SCH) is found in 18-39% of women with a threatened miscarriage and around 70% of women with a SCH will experience vaginal bleeding. Data on the relationship between first trimester vaginal bleeding and obstetric outcome is described mainly in retrospective and noncontrolled studies. It is hypothesized that first trimester bleeding is an indicator of a general tendency for complications (such as: preterm premature rupture of membranes (PPROM), preterm delivery (< 37 weeks gestation; PTD) low birth weight (<1500g; LBW) neonates, small for gestational age (SGA) neonates, placenta previa, placental abruption and stillbirth) later on in pregnancy.~Nowadays, there are not scientific based treatments for the prevention of complications associated with SCH and vaginal bleeding. Nevertheless, recent data have suggested that prophylactic administration of progesterone leads to a significant reduction in the rate of preterm deliveries and SGA neonates among patients with PTD or SGA neonates in the past. Although progesterone administration for threatened miscarriage was not studied, many physicians treat patients with first trimester vaginal bleeding with progesterone. In this era of evidence based medicine, the researchers aim to investigate whether treatment with progesterone for patients with first trimester vaginal bleeding will alter the rates of obstetrical complications and adverse pregnancy outcomes. The researchers hypothesize that treatment with progesterone for first trimester vaginal bleeding will alter the rates of the above mentioned obstetrical complications and adverse pregnancy outcomes.
The purpose of this study is to investigate whether treatment with progesterone for patients with first trimester vaginal bleeding will alter the rates of obstetrical complications and adverse pregnancy outcomes.