First Trimester of Pregnancy


Written by : Dr.M.D.Mazumdar, MD

The body goes through many changes as the foetus grows and develops. A normal pregnancy is 40 weeks (or 280 days) long. It is divided into three stages called trimesters, each approximately 13 weeks long.

A number of features are shared by all the three trimesters, but each trimester also has signs and symptoms that are specific to it.

The first trimester begins with the first day of your last menstrual period and ends with the last day of the 13th week. It is the most important stage in pregnancy in terms of the development of the foetal organs.

By the end of this trimester, all the major foetal organs will have developed and the foetus will begin to look distinctly human.

Missed Period

Pregnancy, in most women, is diagnosed when they miss their menstrual period. Home pregnancy tests are the most commonly used method for confirmation of pregnancy. Since pregnancy is calculated from the first day of the last menstrual period, you are already in your second month by the time pregnancy is confirmed.

Pregnancies can also occur without prior regular menses, e.g. in breastfeeding women, in young girls who have not yet got their period and in post-menopausal women. Sometimes, implantation bleeding can occur at or around the 21st - 28th day after your last menstrual period. This can be mistaken for normal menses.

But implantation bleeding is minimal compared to normal menses, occasionally just a drop of blood. Sometimes, bleeding due to implantation can occur over 4 - 5 days, but it is usually scanty. It is rarely enough to soak your vaginal pad through, although it may stain it considerably.

The First Trimester

Nausea with or without vomiting

Commonly called 'morning sickness of pregnancy' or just pregnancy sickness, many women complain of nausea in the early part of their pregnancies. It appears soon after the first missed periods and decreases by the end of the third or fourth month.

In some women however, nausea and even vomiting can last throughout the pregnancy, right till the last month. This is more so if the woman also has heartburn and acidity as acidity itself is a cause for nausea.

Morning sickness is more common in women in their first pregnancy. In most women, it is not severe enough to affect normal health. Some women, however, have such intense vomiting as to require hospitalization and supportive treatment.

Gastric acidity which contributes to the severity of morning sickness can be controlled by antacids. But morning sickness cannot be completely eliminated by prescription drugs, although it can be kept under control to some extent. Read More ...

Sore Breasts

In many women, sore breasts may be one of the first signs of pregnancy, occurring even before the first missed periods.

The high levels of progesterone needed to maintain pregnancy, also causes the development and growth of the breasts to prepare them for breastfeeding. The maximum growth is near the nipples, causing them to be sensitive and painful to the touch.

Soreness of the breasts can be decreased to some extent by wearing a seamless soft cotton bra that does not irritate the nipples. Read More ...

A sports bra that holds the breasts firmly in place and does not allow much movement can also be helpful in decreasing the discomfort caused by sore breasts.

Many women prefer to wear sports bras throughout their pregnancies as it provides good support to the enlarging breasts.

Although breast growth continues throughout pregnancy, the body adjusts to the growth and the soreness soon decreases in the second trimester. Read More ...

Excessive Fatigue

Excessive fatigue can be one of the presenting symptoms of pregnancy. Progesterone can cause the body to slow down, slowing down the metabolism of food in the gut as well as the entire digestive process.

Lack of sleep at night in the first trimester due to indigestion and heartburn, leg cramps, increased frequency of passing urine, fear of the coming days of pregnancy and delivery can cause you to feel more sleepy and fatigued during the day.

Dehydration due to nausea and vomiting and lack of a nourishing diet due to lack of appetite are other contributing factors.

Supplementing your diet with multivitamin tablets is helpful in decreasing fatigue to some extent. Read More ...

Increased Vaginal Discharge

Progesterone stimulates the cervical glands (the glands at the mouth of the uterus) and as a result, you may find yourself secreting profuse whitish or creamish vaginal discharge.

As long as the vaginal discharge does not smell, does not cause itching or burning and is not brownish in colour (which could indicate the presence of blood) you have nothing to worry about. Read More ...

Excessive Salivation

Many women complain that they suffer from excessive salivation and a metallic taste in the mouth as soon as they become pregnant. Salivation may be so much that their mouth may be constantly full of spit.

It is believed that the salivary glands are stimulated by progesterone to produce more saliva. Read More ...

On Examination:

The uterus is not palpable through the abdominal wall during the first trimester as it remains a pelvic organ till the 12th week, that is, it remains within the cavity formed by the pelvic bones.

On bimanual examination, that is, when the doctor examines a patient with one hand inside the vagina and one on the abdomen, she will feel the uterus definitely enlarged. At 6 weeks, it is about the size of a small plum, at 8 weeks, it is about the size of a small orange and at the end of 12 weeks, it is the size of an average newborn baby's head.

She may feel the uterus contracting and relaxing rhythmically and gently (called Braxton Hick's contraction). You, however, will not feel these contractions.

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