Subfertility: Low Birth Weight and Role of IVF

Introduction

Pregnancy-related complications are a global problem. Every one out of five couples is suffering from infertility. Around 48 million couples globally are suffering from infertility. Sometimes conditions like subfertility are also responsible for pregnancy-related complications. Different treatment modalities like assisted reproductive procedures are used in modern medicine to overcome such pregnancy complications. In-vitro fertilization (IVF) is the most popular method among all fertilization methods. But recently, scientists have pointed out several abnormalities like low birth and low growth patterns among babies born with the help of IVF procedures.

What Is Subfertility?

Subfertility is a condition characterized by being unable to get pregnant even after having unprotected intercourse for more than one year. Subfertility is not similar to infertility. In subfertility, the fertility rate is reduced, but in infertility, fertility is compromised. Subfertility is divided into two types:

1. Primary Subfertility: Primary subfertility is a condition in which the woman cannot conceive for the first time or is seen in men who have never made any woman pregnant.

2. Secondary Subfertility: This is seen in women who were pregnant before but unable to convince in the present situation or men who made women pregnant before could not do so in their present condition.

Most cases of subfertility are related to diseases of the female reproductive system and male genital tract abnormalities. Around 5 percent of these cases can not be treated by any means and are considered cases of infertility. But in certain conditions, the tubal patency and the semen analysis are normal in spite of the presence of fertility-related complications. These conditions are known as unexplained subfertility. Around 30 to 40 percent of cases of subfertility belong to this category.

The risk factors associated with subfertility are:

1. External Factors: Several external factors like smoking, and chronic alcoholism, is associated with subfertility. Also, excessive stress, obesity, excessive exercise, and consumption of fewer calorie is related to subfertility.

2. Loss of Egg: Loss of the egg is one of the biggest problems associated with subfertility. Increased egg and sudden stoppage of the menstrual cycle before the age of 40 is responsible for this.

3. Hormonal Factors: Excessive secretion of androgen (male sex hormone) in the female body is responsible for polycystic ovarian syndrome (PCOS). Such conditions are associated with female infertility. Also, less secretion of sex hormones like testosterone is responsible for defective sperm formation.

4. Infectious Condition: Infections conditions like gonorrhea and chlamydia is responsible for lesions in the genital tract and adhesions of female reproductive structures. As a result, sperm formation is disrupted, and implantation of the fertilized egg is disrupted.

5. Endometritis: In this condition, ovary-like tissue is present outside the ovary, like the pleura, pericardium, and fallopian tube. This causes hormonal imbalance and excessive secretion of inflammatory mediators. These factors disrupt the implantation process.

6. Structural Abnormality: Structural abnormalities of the male genital tract, like varicoceles, are responsible for defective sperm formation or alteration in semen volume. Female problems like septate uterus, dented uterus, and one-sided uterus are associated with implantation problems.

What Is the Role of IVF?

The treatment for subfertility can be divided into two parts. The cause of subfertility can be treated by lifestyle modifications, surgical interventions, pharmacological interventions, and by hormonal therapy. For fertility, purposes assisted reproductive procedures are followed. These include:

1. Intrauterine Insemination (IUI): in this procedure, the sperm is prepared outside, and the prepared sperm is placed inside the ovary.

2. In Vitro Fertilization (IVF): This is the most popular method. In this method also, the sperm is prepared outside. After that, the egg is taken out of the ovary. The fertilization is done outside the ovary in an artificial medium. The embryo is grown in an artificial medium and transferred to the ovary at a particular time.

3. Intracytoplasmic Sperm Injection: In this procedure, a single sperm is injected into the center of the egg through a microscope-like needle.

What Is Low Birth Weight and Its Relation With IVF?

Low birthweight of the infant is associated with babies born with a weight less than 2500 grams. It is independent of gestational age. This condition depends upon factors like socioeconomic and mothers' systemic conditions. Recently its association with IVF has been documented by researchers.

1. Maternal Age: The mother's age is one of the key factors associated with the low birth weight of the child. Women aged 36 years or more are associated with such conditions. Unfavorable conditions for fetal are associated with this. Increased maternal age is associated with poor placental perfusion, and impaired transplacental flux of nutrients may be responsible for such conditions.

2. Habits: Deleterious habits like smoking and alcoholism are associated with subfertility. The continuation of such habits during pregnancy is associated with low birth weight. Specifically, maternal smoking during pregnancy is the most prevalent risk factor. The tobacco toxins cross the placental barrier and reach the fetus's blood. Nicotine, carbon monoxide, and polycyclic aromatic hydrocarbons from smoke are responsible for intrauterine growth restriction. Also, damage to the placental cell membranes is caused by these toxins.

3. Ovarian Stimulation: Ovarian stimuli are given in IVF and other addictive reproductive procedures. Different substances like plasma protein-A (PAPP-A) and human menopausal gonadotropins have direct toxic effects on embryos. These are also responsible for poor implantation environments and diminished endometrial receptivity. As a result, the risk of low birth weight among newborns increases.

4. Effects of Embryo Culture Media: After fertilization, the human embryo grows in the artificial culture media until transferred to the womb. The culture media contain various substances like protein, fat, amino acids, EDTA, antibodies, and many more. These substances are responsible for the methylation of H19 or insulin-like growth factor - 2 (IGF -2). As these factors are essential for development and growth, disruption in their functioning may cause low birth weight.

5. Physical Factors: Physical factors associated with subfertility can affect the child's growth. PCOS, endometriosis, and poor semen count are the parental factors that are associated with low birth weight. Though the exact mechanism is unknown, it can be assumed that hormones and chemotactic events play a crucial role.

Conclusion

Subfertility is a setback in the path of parenthood. This battle can be won with the help of modern medical procedures and processes like IVF. But children born with the help of assisted reproductive procedures are often shown low developmental patterns. Low birth weight is also associated with developmental delays, poor neurological development, poor eyesight, and mental retardation. Proper care before and after the baby's birth and medical supervision is essential to fight these problems.