Fetal Development: Week by Week Guide: Month 9

Fetal Development: Week by Week Guide: Month 9

6 Apr 2022 | 4 min Read


Author | 2574 Articles

There can be no better feeling than seeing two red lines in the pregnancy test kit. The news of expanding the family is indeed very gratifying. Each day, each week and each month brings you closer to a dream that means the world to you and your loved ones. The excitement and anticipation as you step into the month 9 of your pregnancy are unmatchable. You are just a few weeks away from welcoming the biggest happiness into this world. In this article, we will discuss the week by week development of the fetus in the month 9 of the pregnancy.

Month 9 of pregnancy (weeks 36-40): The pain, the associated complications, and discomfort are finally nearing an end. You are in the last phase of pregnancy. The baby is all set to leave the comfort of your womb and see the real world. Each week brings about some new fetal development.

Week 1:

The baby is approximately 2.6 kgs or 5.7 lb with a height of about 47.4 cm or 18.7 inches. The fat layers are slowly developing in the body. This period is also marked by a condition termed as ‘Lightening’ whereby the baby may enter into the birth canal, positioning themselves in the birth position (head down). However, at times the butt may be positioned downwards instead of the head (breech birth). While most of the organs have been developed, the lungs are yet to be matured.

Week 2:

The baby weighs approximately 2.9kgs or 6.3 lbs with a height of about 48.6 cm or 19.1 inches. The toenails continue to grow (reached the end of the toe or even further). The digestive system of the baby is undergoing development and maturation. The baby will continue to exhibit normal body movements within the womb during this week. There is also development and build up of the facial muscles taking place (there would be cute grimaces and frowns).

Week 3:

The baby weighs approximately 6.8 lb or 3kgs with a height of about 49.8 cm or 19.6 inches (head to heel). By this time, most babies are expected to have a head full of hair (the hair will continue to grow). The baby is also slowly putting on weight (~ 1oz per day). The baby skin which was wrinkled all along is undergoing a change (the typically smooth baby skin). The vernix caseosa, a white waxy-like substance that coats the skin of the baby is also slowly gone. Also gone are the fine and soft lanugo hair (hair that mainly covers the fetal body and limbs). The baby is now able to hold and grasp things with their soft and tiny hands. In some cases, being fully developed, the baby may be born during this week.

Week 4:

The baby weighs approximately 7.5 lb or 3.4kgs with a height of about 50.8cm (20 inches). New skin replaces the outer skin layer of the baby. The diameter of the head is approximately 4 inches. There is an increased production of pulmonary surfactants (an amalgamation of proteins and lipids produced by the type II epithelial cells to reduce the surface tension mainly within the alveoli present in the lungs) to ensure that the baby can breathe sans any problem once outside the womb. The baby is within the final birth position and will appear to be all cramped up for space inside the uterus. You will continue to experience the kicks and the punches mainly in the lower abdomen. This week may also bring about the good news that you all have been waiting for with bated breath.

Week 5:

The baby weighs approximately 7.6lb or 3.5kgs with a height of about 20.2 inches or 51.2cm (head to heel). In most cases, the baby is born in this week (week 40). However, at times, the baby may take a week or two (41 – 42 week) to be born. There is nothing to lose sleep over this. Just relax! The contractions and the labour pain could start any moment. The moment is here! Your bundle of joy is finally in your arms, getting to know a new world.



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