Uterus or womb is the main organ where baby grows right from implantation of embryo in the Endometrium (inner lining of uterus) up to delivery. Abnormalities in the uterus are responsible for around 5% couples suffering from fertility issues.
Uterus (Womb) is a muscular organ which is pear shaped. Normal dimensions in non pregnant state are 7.5 cm X 5.0 cm X 2.5-3.0 cm.
Externally it is covered by serosa. Main component of the uterus is its musculature. Uterus is made up of involuntary muscle fibers arranged in specific manner. These muscle fibers are relaxed throughout the pregnancy and are responsible for holding growing baby safe inside the cavity of the uterus. Progesterone is the hormone which relaxes these muscle fibers and thus pregnant lady continues to hold the pregnancy under its effect. Oxytocin is the hormone produced from brain is responsible for the contraction of the muscles and thus it leads to delivery of the baby through cervix (mouth of uterus).
Fallopian tubes open inside the uterus at its upper part on both the sides. Cervix or mouth of the uterus is situated in its lower part which opens in vagina. Cervix is again muscular part having internal and external os (orifices) with length of about 3 cm in between.
Abnormalities of the uterus can cause infertility by interfering with embryo implantation and fetal growth. Uterine factor infertility is relatively uncommon occurring in less than 5 percent of women.
Sometimes a woman is born with a misshapen uterus, such as the bicornuate or horned uterus, which can sometimes be corrected surgically. Large polyps and fibroids can also interfere with fetal growth and are removed usually via a laparoscopy.
Severe pelvic infections (pelvic inflammatory disease, PID) caused by a variety of microorganisms can permanently damage the uterus and tubes. Cancer treatment may also require the removal of the uterus.
If the uterus is absent or severely damaged the only option is to use the services of a surrogate using in vitro fertilization (IVF). A surrogate is a woman who carries the baby to term and delivery.