WELCOME TO THE SECOND TRIMESTER! The fourth month (weeks 13-16 of your pregnancy) is the beginning of the rapid growth of your child, with an accelerated gain in their weight. This month, your belly will start to show, and your enlarged breasts and waistline will feel comfortable in clothes for pregnant women, which seemed a little too large a month ago. Although the serious emotional and physical difficulties of the first trimester will begin to dissolve, the next few months will still require a few adaptations from you.
You are probably counting the length of your pregnancy in months, but the doctor assesses the development of the child in weeks, and it is on the thirteenth week that you cross the magical line that separates you from the period that many women call the “golden season” of pregnancy. Some still have days of feeling unwell, but most women agree that nausea subsides and triggers appetite during this middle trimester, not only for food, but also for sex. In this trimester, many women feel that their much of their pre-pregnancy strength has returned.
Pregnancy Week 13
This week your baby is fully formed and is about the size of a peach – from 6.6 to 7.6 cm (2.6-2.9 inches) from head to tailbone – and its weight is about 15-20 g (0.03 – 0.04 pounds). The size of the head still exceeds the size of the whole body, however. From this moment on, your child will be growing much faster. The face continues to take a distinct shape and the distance between the eyes decreases. The fingers and toes of your little one resumes growing, and the ankles and wrists form. Likewise, genitals become more visible, and the intestines occupy its proper position.
As for the mother, your uterus has grown significantly, will have filled the pelvic area and has begun to grow up towards the belly. The uterus is like a soft, smooth ball. If you still have not gained weight due to morning sickness, now it will begin to change as the nausea goes away.
Tip for this week: Your husband may feel that they are furthering away from you because he does not experience the same physical changes as you. During this period, you should communicate more and get along with each other, share experiences and dreams. Try to encourage your partner to partake in the hassles associated with pregnancy. For example, you can invite him to go with you to the doctor and listen to the child’s heartbeat.
Pregnancy Week 14
Your little one is now between 7.5‑10 cm (2.9-3.9 inches) from head to tailbone, with a weight around 30 g (0.07 pounds). Its ears move from the neck area to the sides of the head, neck becomes longer, and the facial features, chin, and fingerprints continue to take form. In addition to this, your baby can begin to respond to external stimuli. If you put a little pressure on your stomach, your child will try to move away from that push.
As a pregnant woman, you have already probably started wearing clothes for pregnant women. You may also experience constipation since pregnancy hormones can relax the intestines.
Tip for this week: for constipation you can try slow exercising, drinking large amounts of fluid, and eating lots of (preferably raw) fruits and vegetables.
Pregnancy Week 15
Your child is now about 10-13 cm (3.9-5.1 inches) from head to tailbone, with a weight around 50 grams (0.11 pounds). The entire body of the fetus is covered with ultra-thin primary hair called “lanugo”, which will disappear by the time the baby is born. Similarily, eyebrows and hair on the head begin to grow. Their bones are also growing stronger. Your baby may have already started sucking their thumb.
Externally, the uterus of the expectant mother is now at a distance of 7.5‑10 cm (2.9-3.9 inches) from the navel. In a few weeks, your doctor may suggest a quadrant screening for pathology markers, which measure the four substances in your blood — alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), inhibin A and estrogen, which produces the placenta. This test gives more accurate results compared to the AFP test. Amniocentesis, in which a small amount of amniotic fluid is taken with a needle, is usually carried out between the 15th and 18th week of pregnancy. It is monitored using an ultrasound device. Amniocentesis is recommended if a woman is 35 years old and older, as well as if the AFP test and quadrant screening for pathology markers give mixed results.
Tip for this week: get used to sleeping on your left side, as this promotes blood circulation. Lying on your back or abdomen after the fourth or fifth month may increase the pressure on the growing fetus and hinder the flow of blood to the fetus. Try to put a pillow behind you and between your legs when you go to bed. This can help prevent you from rolling over onto your back. You can also buy pillows for pregnant women, which provide support to the whole body.
Pregnancy Week 16
In this week, you child is already 11‑12 cm (4.3-4.7 inches) from head to tailbone, and weighs about 80 g (0.17 pounds). The nails on the hands are fully formed, and lanugo (ultra thin primary-hair) may be growing on the head. Your baby is also moving his arms and legs. The nervous system is in full function and the muscles react to the activity of your baby’s brain. The child’s heartbeat can be heard with ultrasound.
For the mother: your uterus has grown significantly and weighs around 260 g (0.57 pounds). Soon you will feel the first movements of the fetus in the uterus. The movements are similar to the movements of gases, which may feel like tremors or flutters. The baby will move more and more often, as you recognize the movements more and be able to distinguish them. Other changes will occur in your body. The growing fetus needs a large amount of blood, which can sometimes leads to nasal bleeding or varicose veins. Also, your uterus is changing its position upwards, meaning it is not pushing down on your bladder as much, so urination will not be less frequent.
Tip for this week: if the veins in your legs are dilated, try to wear supporting stockings. If possible, raise your legs in order to increase blood flow to the rest of your body.
By the End of this Month
During this month, your child’s fingers and toes are already fully formed. The baby already has eyelids, eyebrows, eyelashes, nails, and hair. It’s teeth and bones become even stronger. The baby can already suck on a finger, yawn, and frown. The nervous system of the child begins working. The reproductive system and genitalia are fully developed, and the doctor can already determine the sex of the baby with an ultrasound scan. The baby’s heartbeats can be heard with a doppler.
By the end of the fourth month, the height of your baby is about 15 cm (5.9 inches), and weight – around 120 g (0.26 pounds).