Human Pregnancy - Landmarks and Pathologies Flashcards
How many fertilisations result in a live infant?
1/4
What is implantation?
The process where the blastocyst embeds into the uterine lining
What is hatching?
Where lytic factors break down the zona pellucida and the blatocyst emerges from it
What is apposition?
The start of implantation. The blastocyst gets near to the uterine epithelium, leading to adhesion
What is invasion?
When the TE cells proliferate and differentiate into cytotrophoblast cells which invade the maternal decidualising endometrium. They anchor the embryo into the decidua. Also, the decidua grows over the blastocyst until it is completely buried in maternal tissue, completing the implantation. Fails in about 30% of cases, either due to embryo maldevelopment or uterine malfunction
What happens during the rest of a normal pregnancy, after invasion?
The conceptus remains within the uterine decidual tissue and the overlying decidua is termed the decidua capsularis.
Why can other mammals not be used for good models for human pregnancy?
The pregnancy may not have the same interaction between maternal tissues and placenta, so studying other species may not provide good information on the processes of human development
What is the definition of an early pregnancy loss?
All pregnancies that are lost before a gestational age of 8 weeks. Many fertilisations are lost within 4 weeks since the last period. Many of these fertilisations are chromosomally abnormal and only survive a few days
What is a miscarriage?
The loss of pregnancy before the baby is viable - usually 23 weeks but not a simple definition. Can include early pregnancy loss, depending on definition. Miscarriage is from a clinically identified pregnancy
What is pre-eclampsia?
It happens in 1-5% of all pregnancies, normally occuring in 2nd half. It’s diagnosed from >140/90mmHg in the mother, and protein in urine. Effects on the infant are variable, some not affected much, some grow slowly in the uterus which leads to a range of problems before and after birth. Severe pre-eclampsia leads to the delivery of the baby to take care of it. The mum’s life could be in danger, or the baby’s, or both
What is pre-term labour?
Before 37 weeks. Occurs in 10% of babies. Half of these due to pre-eclampsia or other conditions which mean the health of each person are in less danger after delivery. Other reasons are due to the early delivery, such as uterine infections, bleeding, or multiple infants. 23-28 weeks is extremely preterm
What is maternal bleeding?
Most common cause of maternal mortality rates back in the day, along with uterine infection. Antibiotics for infections,bleeding often required surgery. Uterine vascular system undergoes complex changes in pregnancy and if they don’t revert back to normal the mother can bleed to death in a few hours.
What are the challenges of studying human pregnancy?
Ethics - any processes must be completely non-deleterious. Studying tissues after delivery gives limited information. Ultrasound gives basic structural outline of the baby, not mechanisms.
Studying embryonic development in other species has limited translation into humans. Different timeframes and structures. Other species have different placentas so hard to study placental malfunctions.
What is parturition?
It is the process of delivery. Commonly lasts from 12-48 hours
What are the stages of parturition?
Dilation of the cervix, emerging of the baby, and expulsion of the afterbirth
