In December 2019, cases of pneumonia of unknown cause first started to appear in Wuhan in China; subsequently, a new coronavirus was soon identified as the cause of the illness, now known as Coronavirus Disease 2019 (COVID-19). Since then, infections have been confirmed worldwide in numerous countries, with the number of cases steadily rising. The aim of the present review is to provide an overview of the new severe acute respiratory syndrome (SARS) coronavirus 2 (SARS-CoV-2) and, in particular, to deduce from it potential risks and complications for pregnant patients. For this purpose, the available literature on cases of infection in pregnancy during the SARS epidemic of 2002/2003, the MERS (Middle East respiratory syndrome) epidemic ongoing since 2012, as well as recent publications on cases infected with SARS-CoV-2 in pregnancy are reviewed and reported. Based on the literature available at the moment, it can be assumed that the clinical course of COVID-19 disease may be complicated by pregnancy which could be associated with a higher mortality rate. It may also be assumed at the moment that transmission from mother to child in utero is unlikely. Breastfeeding is possible once infection has been excluded or the disease declared cured.

ProblemEmbryo implantation depends on the interactions between the developing embryo and the maternal endometrium. Signals originating from the decidua play a critical role in the process of implantation and trophoblast invasion; however, the molecular mechanisms mediating this interaction are poorly understood. The objective of this study was to develop in vitro models that would mimic the processes of attachment, migration, and early invasion of the trophoblast.Methods of studyFirst trimester trophoblast cells (Sw.71 cells) were cultured in low attachment plates to form blastocyst‐like spheroids (BLS). Epithelial‐mesenchymal transition (EMT) characterization during BLS formation was determined by RT‐PCR and Western Blot. The two 3D in vitro culture models consist of (a) trophoblast migration: BLS cultured in suspension (b) trophoblast invasion: human endometrium stromal cells (HESC) plated in the bottom of a 96‐well plate, covered by Matrigel and BLS transferred on top. Matrigel was used to mimic the human endometrial extracellular matrix.ResultsUsing 3D cell culture systems and real‐time imaging, we are able to determine the impact of endometrial factors on trophoblast cell function. Endometrial stromal cells promote blastocyst‐like spheroid migration of trophoblast cells and invasion of the extracellular matrix.ConclusionWe report the characterization of 3D in vitro models to evaluate the interaction between endometrial cells and trophoblast during the process of migration and invasion. The models are useful tools in order to further study the molecular mechanism of embryo‐maternal uterine cells interactions.

HELLP syndrome and the less common acute fatty liver of pregnancy (AFL) are unpredictable, life-threatening complications of pregnancy. The similarities in their clinical and laboratory presentations are often challenging for the obstetrician when making a differential diagnosis. Both diseases are characterised by microvesicular steatosis of varying degrees of severity. A specific risk profile does not exist for either of the entities. Genetic defects in mitochondrial fatty acid oxidation and multiple pregnancy are considered to be common predisposing factors. The diagnosis of AFL is based on a combination of clinical symptoms and laboratory findings. The Swansea criteria have been proposed as a diagnostic tool for orientation. HELLP syndrome is a laboratory diagnosis based on the triad of haemolysis, elevated aminotransferase levels and a platelet count < 100 G/l. Generalised malaise, nausea, vomiting and abdominal pain are common symptoms of both diseases, making early diagnosis difficult. Clinical differences include a lack of polydipsia/polyuria in HELLP syndrome, while jaundice is more common and more pronounced in AFL, there is a lower incidence of hypertension and proteinuria, and patients with AFL may develop encephalopathy with rapid progression to acute liver failure. In contrast, neurological symptoms such as severe headache and visual disturbances are more prominent in patients with HELLP syndrome. In terms of laboratory findings, AFL can be differentiated from HELLP syndrome by the presence of leucocytosis, hypoglycaemia, more pronounced hyperbilirubinemia, an initial lack of haemolysis and thrombocytopenia < 100 G/l, as well as lower antithrombin levels < 65% and prolonged prothrombin times. While HELLP syndrome has a fluctuating clinical course with rapid exacerbation within hours or transient remissions, AFL rapidly progresses to acute liver failure if the infant is not delivered immediately. The only causal treatment for both diseases is immediate delivery. Expectant management between 24 + 0 and 33 + 6 weeks of gestation is recommended for HELLP syndrome, but only in cases where the mother can be stabilised and there is no evidence of foetal compromise. The maternal mortality rate for HELLP syndrome in developed countries is approximately 1%, while the rate for AFL is 1.8 – 18%. Perinatal mortality rates are 7 – 20% and 15 – 20%, respectively. While data on the long-term impact of AFL on the health of mother and child is still insufficient, HELLP syndrome is associated with an increased risk of developing cardiovascular, metabolic and neurological diseases in later life.

Successful implantation requires the coordinated migration and invasion of trophoblast cells from out of the blastocyst and into the endometrium. This process relies on signals produced by cells in the maternal endometrium. However, the relative contribution of stroma cells remains unclear. The study of human implantation has major technical limitations, therefore the need of in vitro models to elucidate the molecular mechanisms. Using a recently described 3D in vitro models we evaluated the interaction between trophoblasts and human endometrial stroma cells (hESC), we assessed the process of trophoblast migration and invasion in the presence of stroma derived factors. We demonstrate that hESC promotes trophoblast invasion through the generation of an inflammatory environment modulated by TNF-α. We also show the role of stromal derived IL-17 as a promoter of trophoblast migration through the induction of essential genes that confer invasive capacity to cells of the trophectoderm. In conclusion, we describe the characterization of a cellular inflammatory network that may be important for blastocyst implantation. Our findings provide a new insight into the complexity of the implantation process and reveal the importance of inflammation for embryo implantation.

As the number of labor inductions in high-income countries has steadily risen, hospital costs and the additional burden on obstetric staff have also increased. Outpatient induction of labor is therefore becoming increasingly important. It has been estimated that 20 – 50% of all pregnant women requiring induction would be eligible for outpatient induction. The use of balloon catheters in patients with an unripe cervix has been shown to be an effective and safe method of cervical priming. Balloon catheters are as effective as the vaginal administration of prostaglandin E2 or oral misoprostol. The advantage of using a balloon catheter is that it avoids uterine hyperstimulation and monitoring is less expensive. This makes balloon catheters a suitable option for outpatient cervical ripening. Admittedly, intravenous administration of oxytocin to induce or augment labor is required in approximately 75% of cases. Balloon catheters are not associated with a higher risk of maternal and neonatal infection compared to vaginal PGE2. Low-risk pregnancies (e.g., post-term pregnancies, gestational diabetes) are suitable for outpatient cervical ripening with a balloon catheter. The data for high-risk pregnancies are still insufficient. The following conditions are recommended when considering an outpatient approach: strict selection of appropriate patients (singleton pregnancy, cephalic presentation, intact membranes), CTG monitoring for 20 – 40 minutes after balloon placement, the patient must be given detailed instructions about the indications for immediate readmission to hospital, and 24-hour phone access to the hospital must be ensured. According to reviewed studies, the balloon catheter remained in place between 12 hours (“overnight”) and 24 hours. The most common reason for readmission to hospital was expulsion of the balloon catheter. The advantages of outpatient versus inpatient induction of cervical ripening with a balloon catheter were the significantly shorter hospital stay, the lower costs, and higher patient satisfaction, with both procedures having been shown to be equally effective. Complication rates (e.g., vaginal bleeding, severe pain, uterine hyperstimulation syndrome) during the cervical ripening phase are low (0.3 – 1.5%); severe adverse outcomes (e.g., placental abruption) have not been reported. Compared to inpatient induction of labor using vaginal PGE2, outpatient cervical ripening using a balloon catheter had a lower rate of deliveries/24 hours and a significantly higher need for oxytocin; however, hospital stay was significantly shorter, frequency of pain during the cervical ripening phase was significantly lower, and patientsʼ duration of sleep was longer. A randomized controlled study comparing outpatient cervical priming with a balloon catheter with outpatient or inpatient induction of labor with oral misoprostol would be of clinical interest.