PLACENTA

Placenta is the first organ to form in a fertilised egg

Placenta is the first organ to form in a fertilised egg

Placenta development is initiated first in human pregnancies, even before the embryo starts to form, according to new research.

A team of scientists at the Francis Crick Institute, London, has found that one of the first steps after egg fertilisation in mammals is the initiation of placenta creation, the organ responsible for providing oxygen and nutrients to the growing baby.

‘This study highlights the critical importance of the placenta for healthy human development,’ said Dr Kathy Niakan, senior author of the study and group leader at the Crick. ‘If the molecular mechanism we discovered for this first cell decision in humans is not appropriately established, this will have significant negative consequences for the development of the embryo and its ability to successfully implant in the womb.’

Once an egg is fertilised the cell rapidly divides and a key process called cell specialisation occurs, where each cell is assigned a specific task.

The team sought to examine the very first cell specialisations by studying donated human embryos that were surplus to in vitro fertilisation (IVF) treatment.

In embryos at the 16-32 cell stage, the team observed a subset of cells which changed shape and polarised, this triggered molecular events that drives placenta specialisation. In particular, atypical protein kinase C (aPKC) was highly expressed at one end of the cell, when aPKC was inhibited the cells no longer became placenta precursors.

This first cell specification is ‘widespread in mammals’ said researchers after they found the same result in cow and mouse embryos, which have divergent mechanisms at later stages of development.

This research, published in Nature, revealed that placenta development starts much earlier than previously thought, before the embryo has implanted into the wall of the uterus, suggesting placenta cells may have important functions in healthy embryo implantation and development.

During IVF treatment, a reliable predictor of successful implantation of an embryo is the presence of placental precursor cells under the microscope. Therefore, this work paves the way towards a better understanding of how to help those struggling to conceive.

‘Understanding the process of early human development in the womb could provide us with insights that may lead to improvements in IVF success rates in the future’ adds Dr Niakan, ‘It could also allow us to understand early placental dysfunctions that can pose a risk to human health later in pregnancy.’

Read more: https://www.nature.com/articles/s41586-020-2759-x

Source: https://www.bionews.org.uk/page_152173

Coronavirus transmitted to newborn through mother’s placenta

Coronavirus transmitted to newborn through mother’s placenta

Pregnant women infected with COVID-19 may pass on the disease-causing virus to their baby through the placenta, researchers in France suggest.

In their study, published in Nature Communications, the authors describe the case of a newborn child which presented with SARS-CoV-2 infection shortly after birth and subsequently suffered neurological conditions consistent with symptoms seen in adults with COVID-19.

Through analysis of the blood of mother and child as well as placenta and amniotic fluid, they give strong evidence for the virus to have been transmitted by the infected mother through the placenta. Scientists hope that taken together with other case reports, this could give indications for the risk and impact of COVID-19 infections during pregnancy.

‘This case study is indeed an important addition to the existing literature,’ commented Dr Ela Chakkarapani from the University of Bristol, who was not involved in the study. ‘Data to date has been suggesting in utero transmission may be occurring and this study adds data to further support that.’

In March 2020, the pregnant woman was hospitalised in Paris with symptoms of COVID-19 and tested positive for the virus. Despite immediate isolation after being born by caesarean section, the newborn boy developed neurological symptoms quickly – including distress and muscle spasms – which mirrored COVID-19-related effects in adults. With his health improving soon after, the baby and his mother recovered and were discharged from the hospital.

The authors conclude that based on their analysis of blood, amniotic fluid and placenta, transmission of the virus via the placenta was very likely in the reported case. This adds fire to the ongoing medical debate over the likelihood of an elevated risk of coronavirus infection for expectant mothers and their children, especially in the context of placenta-transmitted disease. According to the CDC, the major source of transmission to babies is contact with respiratory droplets from mothers or other caregivers immediately after birth.

‘It remains rare for babies to become infected; in 244 live-born babies of infected mothers in the UK, 95 percent had no sign of the virus, and outcomes are similar to non-infected babies,’ commented Professor Andrew Shennan from King’s College London. ‘This report adds knowledge to a possible mechanism of transfer to the baby, i.e, via the placenta while pregnant, but women can remain reassured that pregnancy is not a significant risk factor for them or their babies with COVID-19.’

Read more: https://www.nature.com/articles/s41467-020-17436-6

Women with endometriosis and diffuse adenomyosis at higher risk for smaller babies, study suggests

Women with endometriosis and diffuse adenomyosis at higher risk for smaller babies, study suggests

By I.Soussis, MD, MSc,FRCOG

Fertility Specialist

Researchers have found that pregnant women with both endometriosis and diffuse adenomyosis have a nearly four times greater risk of carrying a baby that is small for its gestational age.

The study from Italy, was published in the journal Ultrasound in Obstetrics and Gynecology.

In the last decade, many studies have reported an association between endometriosis and major pregnancy-related complications, including spontaneous late miscarriage, preterm labor, fetuses small for gestational age (SGA), hypertension, pre-eclampsia, and other issues. But other studies have not reached similar conclusions.

Endometriosis is the disease that the endometrium, the tissue lining the uterus is located outside the uterus. Often is accompanied by adenomyosis, which refers to a condition where the tissue lining the uterus grows into the muscular wall of the uterus.

The reported prevalence of adenomyosis in patients with endometriosis ranges from 20% to 50%. Previous studies have shown that adenomyosis can lead to an increased risk of adverse events in pregnancy, but few studies have paid close attention to the correlation between adenomyosis and pregnancy outcomes in patients with concurrent endometriosis.

Researchers set out to determine whether the maternal and fetal outcomes were different in women with endometriosis alone compared to endometriosis with either diffuse or focal adenomyosis.

Focal adenomyosis occurs in one particular site of the uterus, while diffuse adenomyosis is when the condition is spread throughout the uterus.

Researchers conducted a retrospective analysis of 206 pregnant women with endometriosis, of which 71.8% had endometriosis alone, 18.4% had endometriosis with focal adenomyosis (EFA) and 9.7% had endometriosis with diffuse adenomyosis (EDA).

Conventional risk factors associated with placental insufficiency such as BMI, PAPP-A levels, and mean uterine artery pulsatility index (UtA PI) in the first and the second trimester were found to be significantly associated with EDA, compared to patients with endometriosis alone. There were no statistically significant differences found in EFA patients.

 Interestingly, an analysis showed that EDA was the only independent risk factor for babies who were small for gestational age (SGA), with an overall higher risk of 3.74 in women with EDA compared to those with endometriosis alone.

SGA is a term used to describe a fetus that is smaller than average for the number of weeks of pregnancy.

One explanation for this result is that women with adenomyosis have imbalanced blood flow, with higher blood flow to the uterine adenomyosis area and lower blood flow to the placenta, which could lead to the reduced growth of the fetus.

“The current study shows that diffuse adenomyosis in pregnant women with endometriosis is strongly associated with SGA infants,” the study’s authors concluded.

They added that women with EDA should be treated as high-risk patients for placental dysfunction and should be more closely monitored.

Source: https://endometriosisnews.com/2018/01/03/women-endometriosis-diffuse-adenomyosis-higher-risk-smaller-babies/

Image credit:https://www.healthline.com/health/pregnancy/getting-pregnant-with-endometriosis

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