The Secret of Human Gestation
Today,i have revised some topics on gestation.Gestation started from fertilization untill birth.It’s all lingers around the physiology of pregnancy,the metabolism that occur during pregnancy and lactation. So,i collect all of these information and i write some ‘mini medical journal’ about them.so,for those who want to have my notes,you can ask me..
Now,talking about the secrecy of human gestation,i found something interesting and remarkable throughout learning this topics.Pregnancy is something nature that endowed by Allah to every women in this world.
Therefore,to make it simple to study and remember,i have classified all the topics into several criterias.
1.what are the hormonal changes that playing a role in pregnancy?
2.what are the metabolic changes that happened to a mother during pregnancy?
3.What types of Vitamin that essentially taken by the pregnant women?
4.how placenta looks like and perform its function? (in other words anatomy and histological structure of placenta)
5.what are the complication during pregnancy?
Here,i wanna stress upon the metabolic changes that occur during pregnancy.
Have you ever see a pregnant women who always got drowsiness,pale,faint,fatigue and even vomit during their first phase of pregnancy?why all of these complications appear?
To explain about metabolic changes during pregnancy,we have to classify it into two phases.
Fisrt phase :early pregnancy
Second phase : late pregnancy
First phase;early pregnancy
During this phase,the pregnant woman develop somewhat we call maternal hypoglycemia.This happen due to decrease uptake of glucose from the mother instead it is utilized by the fetus as source of energy.other energy sources include amino acids,fatty acids and ketone bodies.on the other hand,lactate which is produced by placenta is partly used by the fetus as energy sources and the rest return to the liver to be utilized through cori cycle.
After 6 weeks of pregnancy,when the placenta is fully develop,it secretes the placental lactogen and placenta steroid hormones that are consist of estradiol and progesteron(hormon of pregnancy).
First,we’re gonna talk about placental steroid hormones which are estradiol and progesterone.the precursor of these hormones is cholestrol.placenta has good LDL receptor that catch-up circulating cholesterol-rich LDL.both of these hormones promote insulin resistance state and they induce lipolysis due to less bioactive insulin.consequently,they decrease glucose utilization in the mother who is already in hypoglycemic state.so,it allows more glucose accessible to fetus.
secondly,placental lactogen hormone stimulate lipolysis and promote ketosis that contibute to morning sickness.it is functionally similar to Growth Hormone(GH).Gluconeogenis also happened during this period.
Important note to be taken
Actually,the placenta itself cannot synthesize sex hormones due to:
1. placenta lacks capacity to synthesize adequate amount of cholesterol which is precursor of sex hormones and these cholesterol and LDL are necessary for supplying the placenta.
2.placenta lacks 3 important key enzyme for synthesize sex hormones:
– 16 a-hydroxylase for estriol
-17 a- hydroxylase
-17,20 desmolase for estrone and estradiol
so,how to maintain these liver enzyme in placenta in order to produce more sex hormones?
– by fetal adrenal and liver provide these enzymes.
after that,what are matabolic changes that occur during late pregnancy?
-this is due to increased level of anti-insulin hormone
-increased lipolysis tend to increased FFA that leads to Gestational Diabetes (impaired Glucose tolerance).in some cases,after labour,this Gestational Diabetes cease.
What is Gestational Diabetes?
-it’s usually happen to the pregnant women in the late pregnancy
-due to increase of anti-insulin hormone(prolactin,placental lactogen)
so,during pregnancy,the mother need to restrict control of her blood glucose level to prevent fetal anomalies,fetal macrosomia,fetal hypoglycemia,fetal hypocalcemia and hyperbilirubinemia.
-lactosuria might happened.it is accompanied by osmotic polyurea.
what is fetal hypoglycemia?
-in newborn of diabetic mother(gestational diabetes)
-in maternal hyperglycemia,more glucose is passed to fetus
-fetus secreted more insulin
(Islet of Largenhan appear in third month and insulin secretion begin at 5th month)
-fetus secrete more insulin due to B-cell hypertrophy
-develop fetal hyperinsulinemia
Is that essential for the mother to take adequate vitamin during pregnancy?
1.Vitamin A (potentiate by vitamin E)- helps maintanence of fetus
2.Vit D : importance for absorption of Ca in intestine.Although the fetus take Ca only in minute amount but Ca itself poorly absorbed by GIT of mother.
3.Vit K : we give vit K in mother’s diet before giving birth to a child.it is essential for preventing brain hemorrhage of an infant.
continue for next session...
Faculty of Medicine,Cairo University