16 week of pregnancy
With your entry into the sixteenth week of pregnancy, you have largely arrived in the second trimester of pregnancy. This leads to a considerable decrease in the risks of those complications that you initially ran: your body is adapting better to your condition as a pregnant woman. The baby continues to grow in size, and you may already have started wearing maternity clothing.
Child development in the sixteenth week
the development of bones and muscles
The fetus’s spine and back muscles are gradually gaining strength, allowing it to move its head as well. Her cartilaginous skeleton has already started to become bony, but the ossification process will finish only after birth, so as to keep the bones flexible at the time of delivery. At the same time the development of the facial muscles continues, with the child practicing swallowing, sucking and various facial expressions.
the development of sensory organs
During the 16th week the first sporadic eye movements appear; however, his lids are still sealed. Hearing also continues to develop, with tiny bones growing in your baby’s ears, allowing them to hear and react to noises like your voice. His skin remains transparent enough to see his developing blood vessels.
the development of internal organs
The circulatory system and urinary tract continue their development. The baby’s heart is now pumping around 23 liters of blood a day, at the same time his sweat glands are growing in place.
The development of the lungs enters the so-called “canalicular” period, in which the respiratory tree develops with the vascularized bronchi and bronchioles. Development will continue from 16 to 20-24 weeks, when the fetus will ideally be able to breathe. Meanwhile, your baby practicing inhaling and exhaling the amniotic fluid that is protecting him inside the amniotic sac.
The development of the umbilical cord is now complete, with two arteries and a vein protected by the gelatinous substance (called Wharton’s jelly) which covers the cord.
The production of meconium, which will be your baby’s first intestinal excretion after birth, also begins at about this time in the fetal intestinal tract.
the size of the child
The unborn child is now as big as an avocado; it is approximately 12 centimeters long, and weighs around 100 grams.
The movements of the fetus in the 16th week
As you already know, the baby has already started moving his arms and legs.
However, in most cases, the mother cannot perceive these movements before the twentieth week, as the baby is still too small, and is nestled in the “cushion” made up of the placenta and the amniotic fluid.
However, this week you may start to feel a slight throb in your uterus, often referred to as a “quickening” as you begin to feel the baby.
Women with the placenta resting near the back of the uterus will likely feel these movements earlier than those with the placenta resting on the front of the uterine wall.
Women pregnant with their second child generally notice these movements before primiparas.
The uterus in the sixteenth week
In this week, the uterus is positioned between the pubis and your navel, with the height of the bottom (ie the distance between the top of the uterus and the top of the pubis) measuring approximately 16 centimeters.
The changes in the woman’s body
It’s your baby bump that’s undergoing the biggest change this week: it’s now big enough for others to notice.
The round ligaments of the uterus begin to thicken and stretch to support their growth.
It is therefore normal that you now occasionally feel tugs in your abdominal muscles and ligaments, especially when you make sudden movements.
This week, the production of colostrum, the first fluid produced by the breast in preparation for breastfeeding, could begin.
Because of this, some women may notice thick, yellowish fluid oozing from their nipples during the 16th and 17th week.
The ultrasound at the sixteenth week
An ultrasound performed this week will show the baby’s facial features becoming more defined, with the nose, forehead, lips and eyes in their seats. The external genitalia are already developed; therefore the technician performing the ultrasound may already identify the sex of the baby, depending on its position in the uterus. Even the existence of any physical defects (the major ones) can be identified with an ultrasound.
The doctor will also use a Doppler ultrasound to check the fetal heartbeat and to ascertain the baby’s health. According to stories from midwives, heartbeats above 140 per minute mean you’re going to have a girl, below that, a boy. However, there’s no clear scientific evidence to back up their “theory.”
Symptoms of the sixteenth week
Most of the initial pregnancy symptoms are now probably gone; but there is nothing to worry about if you still have some morning sickness, dry mouth, insomnia and poor appetite.
These symptoms are usually more intense in twin pregnancies due to higher levels of estrogen and progesterone.
Other signs and symptoms that are common in the 16th week of pregnancy consist of:
- pain in the hips and back;
- joint and muscle pain;
- a pain in the round ligament of the uterus;
- an enlarged breast;
- visible veins, especially on the abdomen, chest, and breasts (due to increased blood flow);
- memory lapses (pregnancy brain);
- shortness of breath (due to the growing uterus, which puts pressure on the diaphragm, and allows less space for the lungs to function;
- tiredness;
- leg cramps
- constipation;
- indigestion and heartburn ;
- gas and flatulence;
- mood swings;
- nails and hair growing faster (due to high levels of pregnancy hormones);
- sore gums and nosebleeds;
- increased vaginal secretions
- dry itchy skin, with or without a rash, especially around the belly.
When it is advisable to consult a doctor
While it is normal to experience some pain in the pelvic, abdominal and back area, you should look out for the following warning signs:
- intense or constant abdominal cramps, together with bleeding, even in patches;
- severe nausea with excessive vomiting, or diarrhea, continued for more than 24 hours;
- extreme fatigue with constant headache , palpitations, dizziness, upper right abdominal pain and changes in vision (could indicate high blood pressure or preeclampsia);
- symptoms such as burning and pain when urinating, pain in the kidneys or lower back, fever or odorless white discharge (this could indicate a kidney infection or candidiasis.
Some tips for a peaceful pregnancy and a healthy baby
- Drink plenty of fluids to avoid dehydration;
- consider getting a flu shot if you’re pregnant during high-risk season;
- use a sunscreen that defends you from UVA and UVB rays, so as not to worsen the darkening of the skin with sun exposure;
- follow a light exercise routine suitable for pregnancy or sign up for prenatal yoga classes (avoid exercises that involve lying on your back or standing for long periods of time, as these exercises reduce the inflow of blood to the fetus);
- take “prenatal vitamins”, and follow a diet rich in nutrients such as vitamin C and folic acid;
- get used to sleeping on your left side , as this position improves blood circulation reducing the risk of edema and varicose veins: for this purpose, the pregnancy pillow should offer you good support and benefit you significantly (there are various models, for more information read this article );
- submit to all the visits and all the control tests that are prescribed to you (the doctor could also recommend some particular blood and urine tests in the case of high-risk pregnancies).
Katherine Johnson, M.D., is a board-certified obstetrician-gynecologist with clinical expertise in general obstetrics and gynecology, family planning, women’s health, and gynecology.
She is affiliated with the Obstetrics and Gynecology division at an undisclosed healthcare institution and the online platform, Maternicity.com.