• Amniocentesis
• Chorionic Villus Sampling
• Obstetrical Outcome
• Twin Pregnancy

• Abortion, Spontaneous/etiology
• Adult
• Amniocentesis/adverse effects
• Amniocentesis/methods
• Chorionic Villi Sampling/adverse effects
• Chorionic Villi Sampling/methods
• Female
• Fetal Death/etiology
• Humans
• Pregnancy
• Pregnancy Trimester, First
• Pregnancy Trimester, Second
• Pregnancy, Twin
• Premature Birth
• Prenatal Diagnosis
• Twins

The occurrence of early abortion after amniocentesis is a serious problem in the fields of obstetrics and gynecology, and it is always important to discover the factors influencing this phenomenon. The incidence rate has been reported in different studies, even up to about 10%. So far, no studies have been conducted in Iran on the effect of amniocentesis and related complications on early abortion. The aim of this study was to determine the effects of amniocentesis and relevant complications on the incidence of early abortion in pregnant women undergoing amniocentesis.

This cohort study was conducted between March 2014 and March 2016 on pregnant candidates for amniocentesis referred to the perinatology clinic at Ommol-Banin Hospital, Mashhad, Iran. Amniocentesis was performed for all patients with about 20–30cc in the same manner by a perinatologist. Maternal blood group, causes of amniocentesis, amniotic fluid profile (liquid color), status of inserting the needle through the placenta during amniocentesis, amniotic fluid leakage, and bleeding after amniocentesis were considered as exposure factors, and spontaneous abortion after amniocentesis until the end of the 20th week of pregnancy was taken as a consequence. Data were analyzed using IBM-SPSS version 20 via t-test and chi-square. Relative risk (RR) was calculated to determine the causal relationship of exposure with the consequences of spontaneous abortion during the first week after amniocentesis.

This study was performed on 1000 pregnant women with mean age of 33.4±6.0 years (minimum 16, maximum 48 years). The incidence rate of spontaneous abortion after amniocentesis was obtained 1%. There was no association among causes of amniocentesis, maternal blood group, maternal underlying diseases, history of diseases associated with pregnancy, and spontaneous abortion. Based on the chi-square test, a significant statistical relationship was found between amniotic fluid leakage and spontaneous abortion (RR=15.37, p=0.001). There was also a significant statistical relationship between bleeding after amniocentesis and spontaneous abortion; so that in patients with more bleeding, spontaneous abortion was more prevalent (RR=6.83, P=0.001).

According to the results, it seems that amniotic fluid leakage and bleeding after amniocentesis should be considered as two serious complications of amniocentesis, which can cause the incidence of spontaneous abortion in pregnant patients undergoing amniocentesis.

• Abortion
• Amniocentesis
• Complications
• Pregnancy

Amniocentesis is an essential tool in obstetrics. Invasive testing remains the only modality for diagnostic genetic testing and the only way to provide comprehensive testing for chromosomal abnormalities. Despite increasing use of cell free fetal deoxyribonucleic acid (DNA) testing, amniocentesis should still be offered to all women who desire more complete and accurate genetic testing. Counseling patients on the limitations of screening tests is of the upmost importance and amniocentesis should continue to be recommended to confirm positive results from cell free fetal DNA testing or in the case of failed cell free fetal DNA test. As cell free fetal DNA screening has not adequately been studied in multiple gestations, its use is not recommended in this population and invasive testing should be offered. Amniocentesis is also very useful in providing additional information in settings other than genetic testing the second and third trimester. If intraamniotic infection is suspected, but the clinical findings are not enough to guide management, amniocentesis can provide testing that can both immediately clarify the picture (interleukin-6, gram stain, glucose levels) and finally confirm the presence of infection (culture). It can also be used to detect the presence of intrauterine viral infections. Additionally, amniocentesis may be used to test for markers of fetal lung maturity. The American Congress of Obstetricians and Gynecologists recommends that amniocentesis for this indication not be used in cases where late preterm delivery is indicated. It may be useful in guiding decision-making, however, when late preterm delivery is indicated, but when exact timing is unclear. Regardless of the indication, amniocentesis appears to be a relatively low risk procedure with minimal risk to the patient. Additional randomized controlled trials are not likely, as they are not feasible to due extremely high number of participants that would be needed to detect a difference in loss rates. Based on current literature, however, the risk of pregnancy loss from second trimester amniocentesis is low in both singleton and twin gestations. We counsel patients that technique has changed since the original studies in the 1970s and feel comfortable quoting a loss rate of 1/500-1/1000 based on contemporary data.

• Amniocentesis
• Prenatal diagnosis
• Invasive genetic testing
• Procedure related loss rates
• Cell free fetal DNA testing
• Fetal lung maturity
• Intraamniotic infection