The fifth month of your pregnancy is almost complete, which means you are halfway through. Your tiny miracle has already started to move about the amniotic sac, kicking and punching, even if you are yet to feel them. From this week onwards, your baby will be growing around a centimeter every week .
This week is vital for the fetal nervous system development as the nerve cells responsible for the senses of taste, touch, sight and sound are developing in their respective brain areas . Production of new nerve cells slow down at this stage as the already existing ones start growing larger, creating complex connections within themselves.
The arms and legs are almost in their proper proportion , while the bones in the extremities continue to harden or ossify. Your baby can now control his limbs better as the neurons between the muscles and brain are now connected .
A fat layer has already started to form just beneath the skin, although it is still semi-transparent with visible veins and blood vessels . Another big change occurring this week is the formation of a cheese-like, greasy coating, referred to as vernix caseosa, all over your baby’s body. This waxy layer protects the delicate fetal skin, preventing wrinkles, chapping and abrasions due to exposure to the amniotic fluid .
All the internal organs are in working order, with the kidneys producing urine which constitutes a major portion of amniotic fluid . His heart is still beating twice as fast as your own with the heartbeat getting stronger every week .
A special substance called brown fat starts forming over the internal organs and systems this week. This layer is unique to newborns, meant for protecting your baby’s vital organs from any harm due to the temperature extremes during and after delivery .
The fetus is approximately 6 inches (15.24 cm)  long, weighing almost 8.5 oz (240.9 gm) , about the size of a mango.
Your belly is growing larger and rounder every week as the top of the uterus has almost reached your belly button , meaning it has completed half of its journey up your abdomen. The increased blood volume raises your body temperature to some extent, making you feel warmer and perspire oftener than usual . The colostrum (the first fluid secreted by the breasts) production continues with your body preparing for breastfeeding as you may notice a yellowish, thick fluid leaking from the nipples .
Although many first time mothers start to feel their baby move (quickening) at this stage, there is nothing to worry about if you do not feel the flutters. Feeling the fetal movements is related to the positioning of your uterus, as those with the uterus situated toward the front of their abdomen are likely to feel their babies earlier than those with the uterus more toward their back .
The routine second trimester transabdominal ultrasound, called a fetal morphology scan , is usually performed between the 18th and 20th weeks. At this stage, an ultrasound image allows your doctor to see both the external and internal body parts of the baby due to his translucent skin . Another exiting thing during this week’s ultrasound is finding out the gender of the baby (if you do not already know). However, the main purpose of this scan is evaluating the fetal growth and heartbeat as well as checking for any congenital anomaly .
It is also known as the fetal anomaly scan as it can detect many neural tube defects and internal organ malformations such as spina bifida, anencephaly, hydrocephaly, major heart, kidney and limb abnormalities, cerebral palsy and Down’s syndrome . Further scans and tests are performed in case an ultrasound detects any of the above problems. In some cases, a transvaginal ultrasound may also be ordered to check for pregnancy complications like a low lying placenta .
The fetal morphology scan helps to ascertain the health and growth of both babies while looking for any twin pregnancy complications such as conjoined twins or twin-to-twin transfusion syndrome . The babies are captured separately in an ultrasound picture as it is often too difficult to evaluate their growth at once .
Published on June 28th 2014 by Pregmed Editorial Team.
Article was last reviewed on 13th August 2014.