Weekly Pregnancy Guide
The First Trimester of Pregnancy: Week by Week
Pregnancy is an exciting journey that lasts approximately 40 weeks for both the mother and the baby. In this guide, you will find what to expect during the first 10 weeks of pregnancy, the stages of fetal development, and important points to pay attention to. The first trimester includes the most critical stages of your baby’s development, and taking good care of your health during this period is extremely important.
Week 1: The First Steps of Pregnancy
Week 1 of pregnancy is actually a time when you are not yet pregnant. Medically, pregnancy is calculated from the first day of your last menstrual period. Therefore, the first week represents a preparation phase in which your body is getting ready for a possible pregnancy. Ovulation usually occurs around day 14 of the menstrual cycle. During this time, the egg matures in the ovaries and begins its journey toward the fallopian tubes.
Week 2: Ovulation and Preparation
In the second week of pregnancy, an egg cell continues to mature in your body. When ovulation occurs, the egg moves toward the fallopian tubes and prepares to meet sperm cells. The most fertile period for conception is the days just before and immediately after ovulation, when regular sexual intercourse increases the chances of pregnancy.
Week 3: Fertilization and New Life
This is the week when fertilization occurs. When the egg and sperm unite, a new life called a zygote is formed. The zygote travels toward the uterus and begins the implantation process. The baby’s sex is determined by the combination of the mother’s X chromosome and the father’s X or Y chromosome. Although the sex is not yet visible, the genetic structure has already been established.
Week 4: Implantation and Early Symptoms
In week 4, the zygote implants in the uterus and develops into an embryo. Pregnancy symptoms may begin to appear during this period. Missed periods, fatigue, breast tenderness, and mood changes are common. This is an appropriate time to take a pregnancy test, as a blood beta-hCG test can detect pregnancy at this stage.
Week 5: Confirmation of Pregnancy and Early Development
If you notice a missed period and your pregnancy test is positive, congratulations—you are officially an expectant mother. In week 5, your baby’s organs begin to form. The embryo continues to grow rapidly as a cluster of cells and strengthens its attachment inside the uterus. At this stage, the baby is approximately 0.2–0.4 millimeters long.
Week 6: Placenta Formation and Early Symptoms
By week 6, many expectant mothers experience morning sickness, fatigue, and frequent urination. The placenta begins supplying oxygen and nutrients to the baby. This is the week when the baby’s heart starts beating and a basic circulatory system forms. The baby’s length reaches approximately 2–4 millimeters.
Week 7: A Rapidly Growing Life
This week, your baby grows to about 10–12 millimeters. Basic facial features such as the eyes, ears, nose, and mouth begin to form. The umbilical cord starts functioning to deliver nutrients and remove waste. It is often possible to see the baby’s heartbeat on ultrasound. Nausea and vomiting may continue for the mother, but these symptoms usually improve in the coming weeks.
Week 8: Movement and Facial Development
In week 8, your baby is approximately 15 millimeters long. The first body movements begin, although the mother cannot yet feel them. Facial structures continue to develop, and the baby may start opening and closing the mouth. Bone development also becomes more noticeable during this week.
Week 9: Facial and Organ Development
This week, your baby’s facial features develop rapidly. The lips, eyes, and nose become more defined, and the intestines move into the abdominal cavity. Your baby measures about 2–3 centimeters. Mothers may experience breast fullness, heartburn, and indigestion during this time.
Week 10: Kidney Function and Emotional Changes
In week 10, the baby’s kidneys begin producing urine, which mixes with the amniotic fluid and is swallowed by the baby, helping the digestive system function. Nausea and fatigue may start to decrease, but emotional fluctuations can continue due to hormonal changes.
Weeks 11–20 Pregnancy Guide
The Second Trimester: Week by Week
The second trimester is generally a more comfortable period for expectant mothers. The body adapts to pregnancy, and early symptoms often lessen. Meanwhile, the baby’s development continues rapidly. Below are the key developments and considerations between weeks 11 and 20:
Week 11: Organ Development and Weight Gain
By week 11, most of the baby’s organs are fully formed. This is one of the fastest growth periods. The senses of smell, taste, and touch begin to develop, and the external ear canal and eardrum form. Mothers may gain about 450 grams per week on average, though this varies individually. Balanced nutrition is essential for healthy weight gain.
Week 12: Baby’s Movements and Double Screening Test
At week 12, all of the baby’s organs are formed, and growth in size accelerates. You may observe the baby opening and closing the mouth frequently, and even hiccupping on ultrasound. Thumb-sucking may also begin. Between weeks 11–14, nuchal translucency measurement and blood tests (Double Test) are important for assessing the risk of chromosomal abnormalities such as Down syndrome.
Week 13: Growing Uterus and Gender Prediction
In week 13, the uterus continues to grow, stretching the ligaments that hold it in place, which may cause groin pain. These pains are usually normal. Gender prediction may be possible via ultrasound, but definitive determination often requires waiting a few more weeks.
Week 14: Beginning of the Second Trimester
Week 14 marks the start of the second trimester, often considered the most comfortable phase of pregnancy. Early symptoms like nausea and fatigue begin to fade. Mothers who have previously given birth may start to feel fetal movements toward the end of this week.
Week 15: Baby Movements and Lanugo
At week 15, the uterus can be felt externally. The baby’s bones and muscles develop rapidly, and fine hair called lanugo begins covering the baby’s skin, lasting until about week 26. Gender determination may be possible for male babies as the testes and penis become visible on ultrasound.
Week 16: Quadruple Test and Baby Movements
During week 16, the Quadruple Test may be performed to assess the risk of Down syndrome and neural tube defects. Fingernails and toenails begin to grow, and mothers who have previously given birth may feel fetal movements.
Week 17: Calcium Intake and Baby Development
At week 17, subcutaneous fat increases, and the baby’s heart pumps about 30 liters of blood daily. Reflexes such as sucking, swallowing, and blinking develop. Calcium intake is especially important at this stage to support bone development.
Week 18: Increased Movement and Skin Changes
The baby becomes more active and frequently changes position. The skin remains thin and translucent. Mothers may notice skin changes such as melasma (pregnancy mask), which usually fades after birth.
Week 19: Sleep Patterns and Fetal Position
In week 19, fat tissue continues developing. The baby practices different positions in the uterus and typically turns head-down around week 34. Sleep–wake cycles begin forming, and in female babies, the uterus starts developing.
Week 20: Halfway Through Pregnancy
Week 20 marks the midpoint of pregnancy. The uterus reaches the level of the navel and continues rising about one centimeter each week. The linea nigra may darken, usually fading after delivery.
Weeks 31–40 Pregnancy Guide
The Third Trimester: Week by Week
Week 31: Dreams and Baby Movements
Expectant mothers may experience vivid dreams due to hormonal changes and altered sleep patterns. Baby movements are strong and noticeable during this period.
Week 32: Baby’s Position and Emotional Changes
The baby often begins settling into a head-down position. Emotional sensitivity may increase due to physical changes, but these feelings are temporary.
Week 33: Amniotic Fluid and Development
Amniotic fluid reaches its peak level, providing protection and allowing lung development as the baby swallows and absorbs the fluid.
Week 34: Sexual Activity and Breathing Practice
Sexual intercourse is generally safe unless advised otherwise by a doctor. The baby practices breathing movements in preparation for birth.
Week 35: Baby Movements and Birth Preparation
Monitoring baby movements is essential. Babies born at the end of this week often survive without intensive care.
Week 36: Epidural Anesthesia and Preparation
This is a good time to discuss epidural anesthesia options with your doctor. The baby’s birth position is usually established.
Week 37: Approaching Birth
The baby may drop lower into the pelvis. Movements such as stretching, hiccupping, and thumb-sucking are common.
Week 38: Preparing for Labor
Labor can begin at any time. Meconium accumulates in the baby’s intestines and will be passed after birth.
Week 39: Labor Is Near
The likelihood of labor is high. Following your doctor’s guidance and preparing your hospital bag is recommended.
Week 40: Expected Due Date
Week 40 is considered the final week of pregnancy, though delivery may occur later. Staying calm and attending regular checkups is important.
Week 41: Labor Induction
If labor has not started by week 41, your doctor may recommend inducing labor due to increased risks associated with post-term pregnancy.