Your pregnancy, month by month

As a single sperm and an egg come together and later implants in the womb, a new life begins. In the coming nine months huge changes will take place in mom’s body which will ultimately result in a unique, unrepeatable human being.”

First month: The first heartbeats

Once implanted in the uterus, the embryo starts to grow. While at the beginning it is only a group of cells, during the second week a dark spot appears in the back of the embryo, which signals the position of the spine. In the third week all organs start to develop and by the end of it, the heart starts to beat.

The fetus has already head and torso. The neural tube, which runs along the spine, closes and will later form the brain. Small buds form in your baby’s, which will ultimately become your baby’s arms and legs. The cells which will end up forming the liver start producing blood in the embryo.

In week four, your baby is already 4 mm long and weights 1 g. Even if you’re not aware of your new condition, your body starts to change. Your uterus starts to enlarge gradually, the ovulatory cycle is disrupted, and ovaries increase the production of progesterone.
Typically, your breasts enlarge, your areolas darken and your nipples sensitize. Moreover, your enlarged uterus makes you urinate more frequently. In addition, nausea, fatigue and sleepiness are usual in the first pregnancy months. Other frequent symptoms include a feeling of emptiness in the stomach and heartburns.

Second month: Your baby grows three times as large

This stage is characterized by an extremely fast development, as the embryo grows three times as large. Facial traits outline subtly. Your baby’s heart beats 170 times per minute, about twice as fast as the an adult’s. Baby’s head is still too big relative to the body and is inclined on the chest. The body starts to stretch and elongate. Your baby can react to touch –even if you can’t feel your baby moving yet.

By the end of the month, your baby measures 2,2 and 3,3 cm from head to toe and weighs about 4 g. The brain grows, limbs start to form, and eyes without eyelids appear. Mouth, intestine and stomach develop quickly, but do not function yet.

Your waist widens conspicuously. Nausea, dizziness, fatigue and tiredness are likely to continue.

Third month: Your baby’s presence becomes evident

As the third month starts, your baby, hitherto called embryo becomes a fetus. Eyelids, eyebrows and liver start developing. Mouth is delineated and even tiny fingernails grow. In addition, most joints start to form and the first cartilages and ribs appear. Blood circulates between fetus and uterus as the placenta starts to function.

His heart now works autonomously altogether. Sucking reflex and occasional hiccups occur, and the fetus frequently swallows amniotic fluid. Kidneys develop fully and the baby starts evacuating urine to the amniotic fluid. In addition, the thyroid gland is formed and secretes hormones.

Genitalia start to grow and by the end of the first trimester your baby’s sex may be identified. Your baby is now 16 cm long and weighs around 14 – 20 g.

By the end of this month, your baby is completely formed and the skin is covered by a downy growth of hair called lanugo, which protects him. You may gain one or two kilograms, your uterus grows stretching out to the pelvis.

Fourth month: Your baby can hear your voice

In the fourth month the fetus has gained weight at a considerable rate. Your baby’s digestive tract starts working and his or her hands and feet look completely formed. Fingernails sprout and even fingerprints can be seen. Most of the times, your baby’s sex can be determined, although the fetus needs to be in an adequate position.
Your baby’s hair starts to grow. The thyroid gland, which had started to form by the second month, begins to function and produce thyroidal hormone to ensure normal growth. Your baby is able to make their first facial expressions such as frowning, making faces and squinting.

Baby’s retinas are now sensitive to light, event that reaching the mother’s womb. The tiny middle-ear bones vibrate and some first sounds become audible to your baby by the end of week 16. Lungs continue to develop and your baby breathes amniotic fluid to receive oxygen through the placenta. Brain cells multiply dramatically –about 100,000 neurons are produced per minute.
By the end of the month your baby measures about 22 cm from head to toe and weights some 100 g. Most moms-to-be no longer feel nausea or vomit, but constipation, heartburns and flatulence will usually persist. Varicose veins and hemorrhoids may appear, as well as ankle swelling.

Fifth month: definition of sex

Your baby is now about 28 cm long and weighs about 300 g. His/her brain and spinal cord complete their development at this stage. Depending on your baby’s sex, her uterus or his prostate is formed. Starting on week 20, vocal cords are formed and skin is covered by a white thick substance called vernix caseosa, which protects the fetus from their liquid environment.

Most of your baby’s teeth are already in place in the jaws. Your baby already has tiny but full-fledged eardrums so he/she can hear his/her own heartbeats and the noise of his/her own body as he/she bumps into the uterine wall –the baby no longer lives in a silent world. Baby can also hear sounds from outside the uterus and react to rhythms and melodies with movements. You can now feel your baby move, as he or she is very active.

During this month the number of neurons is completed. This new being will never have as much neurons as it has now. Average heartbeat frequency ranges between 140 and 150 per minute.
Your belly is rounded. Constipation and foot and ankle swelling may persist.

Sixth month: Your baby opens the eyes and sleep

In this month, your baby is estimated to make some fifty body movements per hour. You can feel kicks in your upper and lower belly and your sides. Baby skin is no longer translucent, but is very fine and reddish because subcutaneous fat is still insufficient. Your baby is already about 35 cm long and weighs around 880 g.

Facial traits are already well defined and in week 22 your baby opens his/her eyes and has a sleep-wake cycle. In this stage brain cells that control conscious thinking undergo an important maturation process.

The spine starts to take its final shape, with its 33 discs, 150 joints and 1,000 ligaments. To have all bones and muscles fit and explore movement possibilities, your baby practices a lengthy and elaborate drill of exercises every day including punching, kicking and breathing movements. At this stage you may have backaches, which may lessen with adequate exercising.

Seventh month: Your baby’s organs get fit

The baby is already 39 cm long and weighs about 1.5 kg. At this point, you can tell the fetus is complete, but is still important to improve some functions and organs –lungs, for example. Your baby may breathe if born at this moment, but his/her organs are immature despite the fact that the nervous system already controls breathing.

Eyelids are completely formed and can be opened and closed. While the skin is still reddish in color, wrinkles have vanished as a considerable layer of fat has formed under the skin. On the other hand, the volume of amniotic fluid decreases, since the fetus occupies more and more room in the womb, which prevents him from moving as much as months earlier.

You will generally have difficulties to find a comfortable sleeping position. You’ll feel lower belly aches. Your breasts start to secrete small quantities of a watery substance, the colostrum, which will later be newborn’s first food.

Eighth month: the final stage

Your baby is now fully developed and gains weight every day and may gain as much 200 – 250 g a week. Fat continues to build up turning your baby’s skin from red to pink. He or she now measures about 44 cm and weighs some 2.15 kg.

Hair keeps on growing, and tiny fingernails have already formed in your baby’s fingertips. Except for lungs, which are getting ready for birth, all the vital organs are fully formed. Baby is sensitive to light and may contract and dilate the iris, opening the eyes when awake and closing them when sleeping. If your baby is a boy, his testes have already descended into the scrotum and if it is girl, her labia minora are already visible.

As for the immune system, the transmission of antibodies through the placenta starts in this month. Your baby develops defenses to fight against a number of infections. At this stage your baby swallows large amounts of amniotic fluid, which makes him or her urinate as much as half a liter a day.

Your baby will very likely turn head down and fits his or her head in your pelvis, preparing for birth. If this is not the case, don’t worry, as some do it at the last moment. During this month the so-called Braxton-Hicks contractions take place, a kind of drill performed by the uterus before delivery. BH contractions are slight, do not last more than thirty seconds and you may not even feel them.

Ninth month: Time to be born

Your baby is completely formed and has reached maturity; that is, he or she is ready to live in the outer world. At this stage, the baby settles in the lower abdomen, preparing for birth and, although seems to be less active, your baby is able to make more than 200 body movements a day.

Your baby gains about 30 g a day, weighs about 3.5 kg and is 48-52 cm long. Head circumference measures almost the same as abdomen perimeter.

At this stage of pregnancy, lanugo –the fine hair covering baby’s body– and vernix caseosa –a fine fat layer on the skin– appear to help slide the baby through the uterine channel during delivery. Baby’s skull is now fully ossified and exhibits fontanels and sutures which will close months after birth.

Your baby’s immunological system is not yet fully developed, and receives mother’s antibodies through the placenta. Intestines have started to produce a substance called meconium, the first feces, which will be eliminated after birth.

During the last trimester the mother may have backaches, heartburn, ankle swelling, or shortness of breath. All these nuisances will disappear as soon as delivery starts and your baby is born.