Yes it is possible for a couple who are both HIV positive to produce a child who is HIV negative using Preventing Mother-to-Child Transmission (PMTCT) of HIV.

The child is not infected at the moment of conception as sperm and ova do not carry the HIV virus and they are what create the foetus. The baby is usually infected during pregnancy as the mother exchanges blood with her child through the placenta. It is during the delivery that the risk of infection of the child is highest due to exposure to maternal blood and vaginal secretions. The baby can also be infected by the mother’s milk, which contains HIV during breastfeeding.

Mother-to-child transmission of HIV can greatly be prevented through regular testing of pregnant mothers. Free ARVs are given at the hospital to the HIV positive mothers during pregnancy, labor and delivery, after delivery and to the newborn babies for the first few weeks of their life. There are should also be no breastfeeding of the baby.

I am sorry about your sister who has got pregnant at the age of 15. At that age, she is still physically and mentally not ready to have a baby. There are a number of health risks of getting pregnant at an early age.

Most severe among the dangers of early childbearing are:

• Increased risk of both maternal and infant mortality due to the pelvic size not fully developed for delivery.
• The childbirth is likely to be more difficult.
• The baby is likely to be born too early and to weigh too little.
• Poor nutrition of mother and child.
• Increased vulnerability to Sexually Transmitted Infections (STIs) including HIV which carry serious health risks for the mother and baby.

Pregnancy-related complications are the main cause of death in 15-19 year old girls worldwide; girls in this age range are twice likely to die from childbirth or related complications than young women aged 20-24.

You should advice your sister, first and foremost to tell your parents about her pregnancy. It may not be easy but she needs to do it as parental care and support is extremely necessary during pregnancy of a young girl.

Secondly, your sister needs to visit the health centre regularly for checkups during pregnancy to avoid many of the dangers of pregnancy and childbirth. A health worker will help to ensure a safe birth and a healthy baby by:

• Checking the progress of the pregnancy so that if problems are likely, the woman can be moved to a hospital for birth.
• Checking for high blood pressure, which is a danger to both mother and child.
• Giving the two injections which will prevent the mother and her newborn baby from tetanus.
• Giving iron tablets to prevent anaemia.
• Checking that the baby is growing properly inside the mother.
• Giving anti-malarial tablets where necessary.
• Advising on where to go or how to get help if problems arise during the childbirth.

Lastly, advise your sister to think of going back to school after pregnancy. She needs to apologize to her parents for them to support her again with school fees.

The onset and degree of pregnancy symptoms vary within women. Some women experience them within days of conception others take much longer. Some of the common pregnancy symptoms include:

(i) Nausea and vomiting: Many women experience illness in the morning (morning sickness) and others feel nausea throughout the day.

(ii) Breast tenderness:  Due to the increasing amount of HCG hormone that begins at implantation, the breasts may become very tender to touch and may start to enlarge.  The veins in the breasts may become more visible. The nipples may start to darken in colour, become more erect and extremely sensitive. This sensitivity is due to rising levels of hormones.

(iii) Feeling tired/Sluggish/Fatigue
During pregnancy, the body goes through major hormonal changes. The temperature becomes higher due to the amount of progesterone circulating through the body making the pregnant woman feel sluggish. Fatigue is a result of high levels of the hormone progesterone.

(iv) Frequent urination: Pregnancy causes the uterus to swell and to start enlarging for the growing fetus. The uterus puts pressure on the bladder causing the feel for the need for more frequent urination. The need for urinating more frequently becomes worse throughout pregnancy for some women.

(v) Missed periods: There is no ovulation during pregnancy therefore a pregnant woman misses her menstrual periods. Missing your period is not a definitive sign of pregnancy, as stress or other factors may cause irregular periods.

(vi) Irritability: Many pregnant women as easily irritated as a result of the hormonal changes and the need to put up with all the pregnancy symptoms. Many women experience mood swings — feel angry, sad, or happy for no reason when they pregnant.

(vii) Heartburn: Pregnancy hormones will slow down bowel functions to give maximum absorption time of vitamins and nutrients. The stomach may not empty as fast which increases the stomach acid.

(viii) Enhanced sensitivity to smells: Some women become turned off by foods and smells they previously enjoyed. Likewise, some may become suddenly attracted to odors they previously repelled.

At your age of 16, just missing your period for 2 month does not necessarily mean you are pregnant.  It is normal for young girls not to menstruate regularly as their bodies are still growing. Menstruation is affected by so many factors like stress, emotional ups and downs, sickness, nutrition, fear, anxiety to mention but a few.
However, if you have a number of the above symptoms, you need to go to a health centre for a pregnancy test.

Pregnancy can only occur in a few days following ovulation (the release of an egg from the ovary). Ovulation usually takes place at some point between the woman’s periods.
Additionally sperm can survive inside the body for about 5 days while they wait for an egg to be released and the egg takes a few days to travel to the uterus so a woman has high chances of becoming pregnant if she has unprotected sexual intercourse 5 days before ovulation through 3 days after ovulation.
Unfortunately, women have no definite way of knowing exactly when they are ovulating and for a most women ovulation can vary from month to month. Many young girls have irregular periods. There is truly no “safe “day to have unprotected sexual intercourse and guarantee that a woman would not get pregnant.
There are plenty of women out there who have conceived when they thought they were “safe”. Therefore it is best not to assume that there are “safe” days if you don’t want to get pregnant.

The menstrual cycle is the process by which eggs are released from a woman’s ovary, ready to be fertilized by the sperm. The bleeding is only part of the menstrual cycle.

The menstrual cycle starts on the very first day of the bleeding. It continues up to the first day of the next period. The average length of the menstrual cycle is 28 days with some women having longer or shorter cycles.

In the first half of the cycle, levels of the “female hormone” (estrogen) start to rise and make the lining of the uterus (womb) grow and thicken. At the same time, some of the eggs start to ripen, though usually only one matures ready for fertilization.. Approximately 14 days from the start of the bleeding, one egg matures and is released from the follicle on the surface of the ovary and then into a fallopian tube. This is called ovulation.
After the egg has left the ovary it travels through the fallopian tube to the uterus. Hormone levels rise and help prepare the uterine lining for pregnancy.

If the egg is fertilized by a man’s sperm cell and attaches to the uterine wall, the woman becomes pregnant.
If the egg is not fertilized, it will break apart. If pregnancy does not occur, hormone levels drop, and the thickened lining of the uterus is shed off as a combination of blood, tissue and mucus. This is called menstruation or menstrual period. This starts the bleeding that  comes from woman’s vagina. Periods can be light, moderate, or heavy, and the length of the period also varies. While most periods last from three to five days, anywhere from two to seven days is normal.

Menstruation happens after the unfertilized egg dies and if indeed this egg is dead, then you may not make the girl pregnant.  However, if this egg is not yet dead, a boy may get the girl pregnant and more so if it is an adolescent or teenager, most of whom whose cycles is not steady. Let us not forget that it is also hard to gauge how or what time exactly menstruation is really expected to start.