Question

1.Teratogens and its effect to pregnancy

2.Danger signs of pregnancy

Answer 1

​​​​​​TERATOGENS

Teratogen causes permenant change in the structure and/or functions of an organ, acting during the embryonic or fetal life.

Teratogens may be chemical agents or physical agents.

Final result of an abnormal development are : Death, malformations, growth restriction, functional disorder.

Mechanism of teratogenicity

Actual mechanism is unknown. They may affect through following ways;

> Folic acid deficiency

It leads to deficient methionine production and RNA, DNA synthesis. Folic acid us important for the normal meiosis and mitosis. Periconceptional folate feficiency leads to neural tube defect, cleft lips and palate.

> Epoxides or arena oxides

These are the oxidative inter metabolites of many drugs such as hydantoin. They are carcinogenicband teratogenic unless they are detoxifide by fetal epoxide hydrolate.

> Environmental and genes

Abnormalities that are multifactorial depends on the ultimate interaction between the environment and fetal gene mutation. Genotype of embryo and teratogens are important determinants.

> Maternal disease and drugs

Have an increased risk of fetal anomalies. Paternal exposure to the drugs can cause gene mutation and chromasomal anomaly in sperm.

> Homeobox genes

These are group of regulatory genes that control the expression of other genes involved in the normal development of growth and differentiation.

Teratogens like retinoic acid is able to dysregulate the genes to cause abnormal gene expression.

Timing of teratogen exposure and its hazards

- Before D31

Teratogens produce an all or none effect.In this early period of conception, only few cells are there. So any damage at that time is irrepairable.

- D31- D71

It is the critical period for organ formation. Effects of teratogens depend upon;

1- Amount of drug reacting to fetus.

2- Duration of exposure

3- Gestational age at the time of exposure.

- After D71

Development of other organs continues. Diethyl silboesterol related uterine anomalies occur with exposure around 20 weeks.

Most of the drugs are able to cross the placental barrier by simple diffusion.

Some maternal medications and its affects on neonates

Lithium : Ebstein's anomalies, fetal diabetes insipidus, polyhydramnios etc.

Aminoglycoside : Nephrotoxicity

Cytotoxic drugs : Multiple fetal malformations and abortion

DANGER SIGNS OF PREGNANCY

Occurance of some minor ailments in pregnancy is normal. Those ailments include;

-Nausea/vomiting

-Constipation

-Acidity and heartburn

-Back ache

-Leg cramps

-Varicose veins

-Acute edema

-vaginal discharge

But , there are some other signs that may be danger to the mother or baby. They are listed below;

> Pain, pressure and cramps in belly

> Temperature over 100⁰F

> Contraction more than 4 times an hour.

> vaginal bleeding

> Seizures

> Sudden weight gain with edema

> Severe headache with blurred vision

> Difficuty in breathing

All such signs should be monitored and requires immediate medical care.

These danger signs may be due to miscarriage, tubal pregnancy, Preterm baby, Infection, eclampsia etc.