Subjects and procedures
This prospective study involved 167 caucasian women of reproductive age. Subjects were divided into four groups:
1.
Forty-seven no-smoking healthy women with current physiological pregnancy, at least 2 previous at term pregnancies and without any miscarriages or autoimmune disease (control group).
2.
Thirty-six no-smoking healthy women affected by uRPL (defined as 2 or more consecutive abortions before 24th week of gestation, according to the ESHRE guidelines 2017) [
22], without any autoimmune disease (RPL group).
3.
Forty smoking healthy women with current physiological pregnancy, at least 2 previous at term pregnancies and without any miscarriages or autoimmune disease (smoking group).
4.
Forty-four no-smoking healthy women with current physiological pregnancy, at least 2 previous at term pregnancies and without any miscarriages affected by autoimmune hypothyroidism (ahT- diagnosis made by elevated TPOAb and/or TgAb above 350 IU/ml and basal TSH) [
23], but not by other autoimmune diseases (ahT group).
All the women included in this study attended as outpatients the Complex Operative Unit of Gynecology and Obstetrics of the University Hospital Policlinico Tor Vergata, Rome. Women with RPL were followed at the RPL Unit, whereas controls were followed at the Physiological Pregnancy Outpatients Clinic.
Patients were recruited at the amniocentesis stage, and then retrospectively excluded from previous RPL evaluations. Indeed, these patients were previously followed by our RPL unit, before pregnancy, and underwent our standardized diagnostic work-up, which included the following: a) collection of familial and personal medical, gynecological and obstetrical history with specific application to the previous miscarriages; b) gynecological examination; c) transvaginal ultrasound; d) hysteroscopy and, when appropriate, endometrial biopsy; e) endocrine evaluation panel: assay of LH, FSH, prolactin, progesterone in the midluteal phase, TSH, FT3, FT4, pituitary and ovarian androgens, insulin and glucose curve; e) karyotype of both partners; f) immunity panel: lupus anticoagulant, anti-β
2GPI, aCL and anti-annexin V antibodies, anti-thyroid antibodies,
antinuclear antibody (ANA), extractable nuclear antigen (ENA), anti-double stranded DNA antibody (anti-ds DNA), anti-smooth muscle antibody (ASMA) and anti-mitochondrial antibody (AMA); g) thrombophilia screening: protein C, protein S, AT III, APCR, homocysteine; determination of the following mutations: factor V [G1691A Leiden], factor II prothrombin [G20210 A], plasminogen activator inhibitor [PAI-1 4G/5G], methylen tetrahydrofolate reductase [MTHFR C677T and A1298C]. This workup was aimed to identify proven, probable and doubtful causes of RPL [
24‐
27].
When all the above known causes for pregnancy loss had been discarded, women were diagnosed with unexplained RPL and were included in this study. Women with a history of at least 2 normal pregnancies at term, without any miscarriage were followed according the standardized protocol used in our unit, which complies with the NICE Clinical Guidelines [
28].
In a first step, all women underwent amniocentesis, because of a 35 or more years old maternal age, positive first trimester screening, parental genetic disease, previous offspring affected by chromosomal abnormalities, were included in the study. In a second step, only patients received amniocentesis due to maternal age, were included in data analysis. Patients with other indications, such as positive first trimester screen or parental genetic diseases, were excluded and therefore not included in the analysis, since these factors may be considered as a bias, and therefore they would have affected the outcome variable.
Only singleton pregnancies were included in the study, and amniocentesis was performed at a gestational age of 16–18 weeks. Pregnancies with a fetus affected by chromosomal defects were excluded from this study.
An ultrasound check has been performed for all patients before amniocentesis by using an ultrasound Hitachi Logos equipped with a transabdominal 3,5 MHz probe. Fetal morphology, placental insertion, amniotic fluid, and FHR were checked. The skin was sterilized by topical povidone-iodine solution application. Amniocentesis was performed in a sterile environment and under continuous ultrasound guidance, by using a 20-gauge 20-cm needle. The easiest accessible and deepest amniotic fluid pocket, which ensure the minimal fetal presence was chosen, taken also into account maternal viscera and vasculature safety. The first milliliter of amniotic fluid was discharged as a standard protocol in clinical practice, and other 20 ml were collected for
the cell culture. An ultrasound check was performed soon after the procedure and one hour after the procedure [
29].
After the amniocentesis, the discarded aliquot of amniotic fluid, after fetal karyotyping, was used to assess the presence of aCL antibodies IgM and IgG, and anti-β2GPI antibodies IgM and IgG. These discarded aliquots were obtained only after written informed consent. The present study was carried out in accordance with the Declaration of Helsinki, modified Tokyo 2004, and was approved by the Institutional Review Board (IRB) of Policlinico Tor Vergata University Hospital (protocol number: R.S. 64/15). Any collected information was anonymised and de-identified prior to analysis.