Uterine Artery Pulsatility Index and Sub endometrial Blood Flow in Unexplained Recurrent Miscarriage

Abstract

Spontaneous abortion is the most common complication of pregnancy and is defined as the passage of a pregnancy prior to completion of 20 weeks gestation. It implies delivery of all or any part of the products of conception, with or without a fetus weighing less than 500gm.Recurrent abortion in its broadest definition is defined as 2 to 3 or more consecutive pregnancy losses before 20 weeks of gestation, each with a fetus weighing less than 500gm. Although the true incidence of spontaneous abortion is unknown, approximately, before the end of the first trimester, 30%–50% of conceptions end in spontaneous abortion. Most losses occur at the time of implantation. 15%–20% of clinical pregnancies end in spontaneous abortions (Gupta et al., 2007). The exact pathophysiology resulting in uterine expulsion of the contents of conception remains unknown. In complicated early pregnancy the uteroplacental circulation demonstrates flow characteristics that are strikingly different from those of normal early pregnancy. In abnormal pregnancies, increased flow within the intervillous space is demonstrated. Uterine receptivity is likely to be regulated by a number of factors including uterine perfusion and of great importance in achieving a normal pregnancy. Studies suggest that uterine artery perfusion may regulate endometrial receptivity, and that poor uterine perfusion could be one of the causes of unexplained abortions and, probably, of faulty implantation (Buckett and Regan, 2003). The aim of the present study was to compare uterine artery pulsatility index (PI) and subendometrial flow resistance index (RI) between women with no history of abortion and women with recurrent pregnancy loss of unexplained cause, and to evaluate the relationship between both of them in correlation to their hormonal profile. In this study, age group ranged from 18 years to 35 years and with mean ± SD 27.975 ± 4.687 years. They were divided into two groups: patients group consisted of 30 patients with age ranged from 20 years to 35 years and with mean ± SD 30.7 ± 4.00 years, and control group consisted of 30 patients with age ranged from 18 years to 35 years and with mean ± SD 30.1 ± 4.7 years. All patients were of the same socioeconomic status. There were no abnormal findings in the personal history, menstrual history, and obstetric history. Special interest was directed towards past history of systemic diseases such as diabetes mellitus, hypertension, renal disease, past history of infants with chromosomal abnormalities such as trisomy 21, history of consanguinity, and past history ofendocrine and autoimmune disorders that might affect the hemodynamic indices (e.g. thrombo-cytopenia, thyrotoxicosis, antiphospholipid antibody syndrome …..etc.); and there were no abnormal findings in all of them. Hormonal profile including thyroid-stimulating hormone, free thyroxin (T4), progesterone levels on day 21 of the menstrual cycle, Anticardiolipin antibody, antilupus antibody, and titers for (toxoplasma, HSV, rubella and CMV) were within normal range. Uterine artery PI was measured in the luteal phase of spontaneous cycles. Uterine artery PI was significantly higher in the recurrent miscarriage group (2.5±0.3) compared to the control group (2.2±0.4) with no statistically significant difference between the pulsatility indices of the right and left uterine arteries within the two groups, the right uterine artery PI of the recurrent pregnancy loss group was 2.22±0.34 while it was 2.42 ±0.29 in the control group, and The left uterine artery PI of the recurrent pregnancy loss group was 2.26 ± 0.38 while it was2.03 ±0.42 in the control group. It was also found that the occurrence of flow velocity waveform (FVW) of C type was more to happen in the control group than the recurrent pregnancy loss group; the incidence of the C wave for the controls was 63.3% on the right side, 63.3% on the left side; and it was 12% on the right side, 90% on the left side for the recurrent pregnancy loss group. Meanwhile, the occurrence of B wave was more to happen in the control group than the recurrent pregnancy loss group, it was 33.3% on the right side, 30% on the left side in the controls; and it was 20% on the right side, 33.3% in the left side in the recurrent pregnancy loss group. 23.3% of the patients had FVW of the A type on the right side, 26.7% on the left side. 16.7% of them had exhibited loss of diastolic flow on the right side and 6.7% loss of diastolic flow on the left side. Neither of the two criteria was found in the control group. The detection rate of subendometrial blood flow in the current study was 90% in the recurrent pregnancy loss group and 100% in the control group. As loss of diastolic flow was observed in one of our recurrent pregnancy loss patient, none of our control had suffered this obstacle. It was found a significantly higher subendometrial blood flow RI in the recurrent pregnancy loss group compared to the control group.The RI of the subendometrial blood flow of the recurrent pregnancy loss group was 0.87 ±0.19 while that of the control group was 0.76±0.19 (p-value = 0.025).