The document discusses fetal growth and development and how drugs can influence it. It describes the typical stages of fetal growth from the pre-embryonic stage through the fetal stage. Key aspects of growth are covered for each trimester of pregnancy. Factors that can affect fetal growth like genetics, maternal health, nutrition, and drug use are examined. The risks of drugs passing from the mother to the fetus are summarized, including potential direct harm to the fetus or indirect issues from reduced blood flow or oxygen. Strict evaluation of drug safety during pregnancy is needed given limited research.

1. FETUS GROWTH AND
ITS INFLUENCE WITH DRUGS
BY
KAVIYA AP
PHARM D INTERN

2. INTRODUCTION II
• Prenatal or antenatal development is the process in which embryo or fetus
gestates during pregnancy from fertilization until birth.
• It is also known as fetal development or embryology.
• Development biology is the study of the sequences of events from fertilization of a
secondary oocyte by a sperm cell to the formation of an adult organism.

4. FETAL
LENGTH
• In the earlier weeks, length of the fetus is measured from vertex to the coccyx.
• While after mid-pregnancy, the measurement of the fetus is determined from the
vertex to the heel.

6. PREMATURE INFANT
• A premature birth is a birth that takes place more
than three weeks before the baby’s estimated due
date.
• In other words, a premature birth is one that occurs
before the start of the 37th week of pregnancy.
• Premature babies , esp those born very early, often
have complicated medical problems.
• Factors related to premature include :
Poor nutrition , use of social drugs, certain infection and
abnormal uterus.

7. MACROSOMIC INFANT
• Macrosomia is a term that describes a baby who is
born much larger than average of their gestational
age.
• Baby’s with macrosomia weighs over 4kg.
• Diabetes in mother is the most common cause of
macrosmoic babies.
• When mother has high blood sugar,she can pass
that along to her baby.All these extra sugar and
extra insulin that made fast growth and deposit of
fat.

8. AGE OF THE FETUS
Gestational age :
• Based on 28 days cycle
• It is calculated from the last menstrual period.
• About 280 days or 40 weeks –
which is first day of the LMP to the birth of the infant.
• GA is also referred to as no. of weeks pregnant.

9. GROWTH OF THE FETUS
• The fetal growth shows linear increase until the 37 weeks and thereafter it
tends to plateau.
• It is controlled by genetic factors in first half and environmental factors in
the second half of pregnancy.
• At term the average weight in India varies from 2.5kg – 3.5 kg

10. FACTORS
AFFECTING THE
FETUS GROWTH
Genetic : predominant control is genetic
Parental height and weight (tall and heavier mothers will have heavier babies)
Fetal sex : A male fetus will have 100 to 200g weight more than the
female at term.
Race : European race will weigh more than Indian babies
Maternal age : Mothers over age of 35 will tend to have small
babies
Socio-economic and nutritional – Average weight of babies is born
to lower social class.
Birth order : Fetal weight rises from first to second pregnancy
Smoking : It reduces mean weight from 200 to 400gms

11. The growth and development of the fetus is typically divided into three stages :
• Pre-embryonic stage : Fertilization to 2-3 weeks.
• Embryonic stage : 4-8 weeks of gestation.
• Fetal stage : 9 weeks to birth

12. • The first 2 weeks of prenatal development are
referred to as the pre-embryonic stage.
• A developing human is referred to as
an embryo during weeks 3–8, and a fetus
from the ninth week of gestation until birth.
PRE-EMBRYONIC STAGE

13. • The embryonic stage of gestation is the period after
implantation, during which all of the major organs and
structures within the growing mammal are formed.
• Once the embryo is fully formed, it expands, grows,
and continues to develop in what is known as the fetal
development stage.
EMBRYONIC STAGE

14. • A fetus is a prenatal human being between
the embryonic stage and birth.
• The fetal stage extends from the beginning of the ninth
week after fertilization to about 38 weeks after
fertilization, which is the average time of birth.
• The fetal stage lasts a total of approximately 30 weeks.
FETAL STAGE

15. FIRST TRIMESTER
• The first trimester will span from conception to 12 weeks.
• This is generally the first three months of pregnancy.
• During this trimester, baby will change from a small grouping of cells to a
fetus that is starting to have a baby’s features. have a baby’s features.

16. Month 1 (weeks 1 through 4)
As the fertilized egg grows, a water-tight sac forms
gradually filling with fluid. This is called the amniotic
helps cushion the growing embryo.
During this time, the placenta also develops. The
round, flat organ that transfers nutrients from the
baby, and transfers wastes from the baby.
In these first few weeks, a primitive face will take form
dark circles for eyes. The mouth, lower jaw and throat
developing. Blood cells are taking shape, and circulation
The tiny "heart" tube will beat 65 times a minute by the
fourth week.
By the end of the first month, baby is about 1/4 inch
than a grain of rice.

17. Month 2 (weeks 5 through 8)
Baby's facial features continue to develop. Each ear
fold of skin at the side of the head. Tiny buds that
into arms and legs are forming. Fingers, toes and eyes
forming.
The neural tube (brain, spinal cord and other neural
central nervous system) is well formed now. The
sensory organs begin to develop too. Bone starts to
cartilage.Baby’s head is large in proportion to the rest of
this point.
At about 6 weeks, baby's heart beat can usually be
After the 8th week, baby is called a fetus instead of an
By the end of the second month, baby is about 1 inch
weighs about 1/30 of an ounce.

18. Month 3 (weeks 9 through 12)
Baby's arms, hands, fingers, feet and toes are fully formed. At this
starting to explore a bit by doing things like opening and closing
mouth.
Fingernails and toenails are beginning to develop and the external
formed. The beginnings of teeth are forming under the gums.
reproductive organs also develop, but the baby's gender is difficult
on ultrasound.
By the end of the third month, baby is fully formed. The baby’s
urinary systems are also working and the liver produces bile.
At the end of the third month, baby is about 4 inches long and
ounce.
Since baby's most critical development has taken place, chance
of miscarriage drops considerably after three months.

19. SECOND TRIMESTER
• This middle section of pregnancy is often thought of as the best part of the experience.
• By this time, any morning sickness is probably gone and the discomfort of early pregnancy has faded.
• The baby will start to develop facial features during this month. Mother may also start to feel movement as baby flips
and turns in the uterus.
• During this trimester, many people find out the sex of the baby. This is typically done during an anatomy scan (an
ultrasound that checks baby’s physical development) around 20 weeks.

20. Month 4 (weeks 13 through 16)
Baby's heartbeat may now be audible through an
called a doppler.
The fingers and toes are well-defined. Eyelids,
eyelashes, nails and hair are formed. Teeth and bones
denser. baby can even suck his or her thumb, yawn,
make faces.
The nervous system is starting to function. The
organs and genitalia are now fully developed, and
on ultrasound if she is having a boy or a girl.
By the end of the fourth month, baby is about 6 inches
weighs about 4 ounces.

21. Month 5 (weeks 17 through 20)
At this stage, Mother may begin to feel baby moving
is developing muscles and exercising them. This first
called quickening and can feel like a flutter.
Hair begins to grow on baby's head. baby's shoulders,
temples are covered by a soft fine hair called lanugo.
protects baby and is usually shed at the end of the
of life.
The baby's skin is covered with a whitish coating called
caseosa. This "cheesy" substance is thought to protect
from the long exposure to the amniotic fluid. This
just before birth.
By the end of the fifth month, baby is about 10 inches
weighs from 1/2 to 1 pound.

22. Month 6 (weeks 21 through 24)
If you could look inside the uterus at baby right now,
would see that baby's skin is reddish in color,
veins are visible through the baby's translucent skin.
finger and toe prints are visible. In this stage, the
to part and the eyes open.
Baby responds to sounds by moving or increasing
You may notice jerking motions if baby hiccups.
By the end of the sixth month, baby is about 12
and weighs about 2 pounds.

23. Month 7 (weeks 25 through 28)
Baby will continue to mature and develop reserves of
At this point, the baby's hearing is fully developed.
changes position frequently and responds to stimuli,
sound, pain and light. The amniotic fluid begins to
If born prematurely, baby would be likely to survive
seventh month.
At the end of the seventh month, baby is about 14
and weighs from 2 to 4 pounds.

24. THIRD TRIMESTER
• This is the final part of pregnancy. Each week of this final stage of development helps baby
prepare for childbirth. Throughout the third trimester, baby will gain weight quickly, adding
body fat that will help after birth.
• The typical, full-term pregnancy is 40 weeks, which can take into a tenth month. It’s also
possible that women can go past your due date by a week or two (41 or 42 weeks).

25. Month 8 (weeks 29 through 32)
Baby will continue to mature and develop reserves of body
Mother may notice that baby is kicking more.
Baby's brain is developing rapidly at this time, and baby
hear. Most internal systems are well developed, but the
still be immature.
Baby is about 18 inches long and weighs as much as 5

26. Month 9 (weeks 33 through 36)
During this stage, baby will continue to grow and
The lungs are close to being fully developed at this
Baby's reflexes are coordinated so he or she can
the eyes, turn the head, grasp firmly, and respond
light, and touch.
Baby is about 17 to 19 inches long and weighs from
pounds to 6 ½ pounds.

27. Month 10 (Weeks 37 through 40)
In this final month, pregnant women could go
time.One may notice that baby moves less due to tight
this point, baby’s position may have changed to
birth.
Ideally, the baby is head down in uterus and mother
uncomfortable in this final stretch of time as the baby
down into your pelvis and prepares for birth.
Baby is ready to meet the world at this point and
to 20 inches long and weighs about 7 pounds.

28. Some women are more likely than others to give birth to twins. The factors that increase the
odds include:
•Advancing age of the mother – women in their 30s and 40s have higher levels of the sex
hormone estrogen than younger women, which means that their ovaries are stimulated to
produce more than one egg at a time.
•Number of previous pregnancies – the greater the number of pregnancies a woman has
already had, the higher her odds of conceiving twins.
•Heredity – a woman is more likely to conceive fraternal twins if she is a fraternal twin, has
already had fraternal twins, or has siblings who are fraternal twins.
•Race – Black African women have the highest incidence of twins, while Asian women have
the lowest.
•Assisted reproductive techniques – many procedures rely on stimulating the ovaries with
fertility drugs to produce eggs and, often, several eggs are released per ovulation.
Factors that increase the odds of having twins

29. Identical or ‘monozygotic’ twins
Around one in three sets of twins is identical.
This occurs because the fertilised egg divides in two while it is still a tiny
collection of cells.
The self-contained halves then develop into two babies, with exactly the same
genetic information.
Twins conceived from one egg and one sperm are called identical or
‘monozygotic’ (one-cell) twins. The biological mechanisms that prompt the single
fertilised egg to split in two remain a mystery.
Approximately one quarter of identical twins are mirror images of each other,
which means the right side of one child matches the left side of their twin.

30. Fraternal or ‘dizygotic’ twins
Around two in three sets of twins are fraternal.
Two separate eggs (ova) are fertilised by two separate sperm,
resulting in fraternal or ‘dizygotic’ (two-cell) twins.
These babies will be no more alike than siblings born at separate
times.
The babies can be either the same sex or different sexes, with the
odds roughly equal for each.

31. Gestation for twins
The normal length of gestation for a single baby is around 40 weeks.
However, gestation for twins, either identical or fraternal, is usually around 38
weeks.
This shorter time is due to the increased demands on the mother’s body, and the
inability of the babies to receive all the nutrients they need in utero.
Since twins are usually premature, they are more likely to have lower birth
weights. Prematurity is associated with increased risk of a number of disorders,
including jaundice.

32. Giving birth to twins
Childbirth can give rise to complications when just one baby
is present, so twins present extra potential for difficulties.
It is advised that women carrying twins give birth in hospital,
rather than at home.
The babies can be delivered vaginally, but caesarean section
delivery may be considered a better alternative in some
circumstances.

33. Drugs play an important role in improving human health and promoting well-being. However to produce the desired
effect, they have to be safe, efficacious and have to be used rationally. In general, drugs unless absolutely necessary
should not be used during pregnancy because drugs taken by a pregnant woman can reach the fetus and harm it by
crossing the placenta, the same route taken by oxygen and nutrients, which are needed for the growth and development of
fetus.
While avoiding medications when pregnant may be desirable, it is often not possible and may be dangerous because some
women enter pregnancy with medical conditions that require ongoing and episodic treatment (e.g. asthma, epilepsy,
hypertension). Also during pregnancy new medical problems can develop and old ones can be exacerbated (e.g. migraine
headache) requiring pharmacological therapy. Failure to manage conditions like these may affect the health of both the
mother and her infant.
Some drugs like vitamins, minerals, iron and dietary supplements are essential for the health of pregnant woman and the
fetus. It has been reported that about 8% of pregnant women need drug treatment due to various chronic diseases and
pregnancy related complications.Many women take medications in the early weeks of pregnancy before realizing that
they are pregnant. More than 90% of pregnant women take prescription or nonprescription (over-the-counter) drugs or
use social drugs such as tobacco or alcohol or illicit drugs at sometime during pregnancy. The fact that certain drugs
given during pregnancy may prove harmful to the unborn child is one of the classical problems in medical treatment.
PREGNANCY AND DRUG USE

34. Pregnant women are usually excluded from medical trials and results from animal studies need not apply to human
population. Hence treating pregnant women with some drugs is a problem and most clinicians have a rather restricted
approach to the use of drugs during pregnancy.
Fear of causing fetal harm and death through medication use in pregnancy has resulted in many challenges to clinical
research about the safety of drugs in pregnancy. Therefore medication safety information in pregnancy is actually
obtained through case reports, epidemiological studies and animal studies; all of which have limitations, that make
determining risks of a drug use during pregnancy difficult.
A study in 2001 found that there was not enough information about the risk or safety of more than 90% medications
approved by FDA between 1980 and 2000 when taken during pregnancy. This makes it difficult for women and health
care providers to decide whether to use medications during pregnancy or not.
Despite the paucity of information on the safety of drugs in pregnancy, the statistics on over the counter (OTC) and
prescription drugs used in pregnancy indicate that drug use in pregnancy is wide spread

35. HOW DRUGS AFFECT THE FETUS
Drugs that a pregnant woman takes can affect the fetus in several ways.
1. They can act directly on the fetus causing damage or abnormal development
leading to birth defects or death.
2. They can also alter the function of the placenta usually by constricting blood
vessels and reducing the blood supply of oxygen and nutrients to the fetus from
the mother and thus resulting in a baby that is underweight and underdeveloped.
3. Moreover they can cause the muscles of the uterus to contract forcefully;
indirectly injuring the fetus by reducing the blood supply or triggering pre-term
labor and delivery.

36.  In 1979, the Food and Drug Administration developed a system determining the teratogenic risk of drugs
by considering the quality of data from animal and human studies. It provides therapeutic guidance for
the clinician.

37. SOCIAL DRUGS
• In addition to counseling pregnant women regarding use of various prescribed and
non-prescribed medications during pregnancy, other substances that are also used
by some women during pregnancy should be overlooked.
• They should be informed about the risk of using the following substances during
pregnancy.hould be informed about the risk of using the following substances during
pregnancy

38. ALCOHOL
• Fetal Alcohol Syndrome is one of the most serious consequences of drinking
during pregnancy.
• Worldwide incidence of Fetal Alcohol Syndrome is 1:2000 live births.
• Risk of miscarriage almost doubles for women who drink alcohol in any form
during pregnancy and birth weight of babies is substantially below normal.
• This syndrome includes inadequate growth before or after birth, facial defects, a
small head, mental retardation and abnormal behavioral development.
• Factors that contribute to the expression of this syndrome are poor nutrition,
smoking, drug abuse, genetic disposition and low socio-economic status.

39. CIGARETTE SMOKING
• Maternal smoking is one of the few known preventable causes of prenatal morbidity and
mortality.
• The most consistent effect of smoking on the fetus during pregnancy is a reduction in birth
weight.
• Birth defects of heart, brain and face are also more common among babies of smokers.
• Risk of sudden infant death syndrome (SIDS), mis-located placenta (placenta previa),
premature detachment of placenta (placenta abruptio), premature rupture of the
membranes, preterm labor, uterine infections, miscarriages, stillbirths, premature births are
increased.
• Changes in uterine and placental oxygenation may be the cause of infant death, pre-
maturity or spontaneous abortions. Therefore all women should be informed of the risk of
smoking on the fetus and encouraged to quit smoking during pregnancy

40. PLACENTA PREVIA

41. PLACENTA ABRUPTIO

42. CAFFEINE
• Caffeine is found in various quantities in many beverages, analgesics, diet aids and
stimulants, Hence it is the most commonly ingested drug during pregnancy.
• Evidence suggests that consuming caffeine during pregnancy poses little or no risk
to the fetus. Caffeine contained in coffee, tea, some sodas, chocolates and some
drugs is a stimulant that readily crosses the placenta to the fetus.
• If taken in high dose it may stimulate the fetus increasing heart and breathing rate.
Caffeine also may decrease blood flow across placenta and decrease the
absorption of iron; increasing risk of anemia

43. ILLICT DRUGS
• Use of illicit drugs like cocaine and opioids during pregnancy can cause
complications and serious problems in the developing fetus and the newborn.
• Growth of fetus is likely to be inadequate and premature birth defects are more
common.
• Cocaine crosses the placenta, constricts the blood vessels reducing blood flow to
the fetus. The reduced blood and oxygen supply to the fetus slows the growth of
bones and intestine.
• Use of cocaine can also cause complications during pregnancy. Among women
who use cocaine throughout pregnancy, 31% have preterm delivery and 15% have
premature detachment of placenta. The chances of miscarriage also increase.

44. CONCERNS WITH OTC DRUGS
• In India due to easy availability of drugs coupled with inadequate health services,
increased proportion of drugs are used as self medications for common
complaints and infective conditions as compared to prescribed drugs. Hence these
consumers always face the threat of adverse drugs reactions and drug
interactions.
• While many OTC drugs can be used during pregnancy under a physician's
supervision, some are known to be unsafe. As indicated on product labels, women
who are pregnant, who may be pregnant, or who are nursing should consult a
doctor before taking OTC medication.
• is labeled as natural

45. • Aspirin is one OTC drug that should be avoided in the last three months of pregnancy. In
1990, the FDA issued a warning that it is especially important not to use aspirin during the
last trimester of pregnancy unless specifically directed to do so by a physician because it may
cause problems in the unborn child or complications during delivery.
• OTC non-steroidal antiinflammatory drugs such as ibuprofen also carry the same warning
about use during the third trimester.
• Experts stress that much is not known about the effects of herbs and dietary supplements on
a growing fetus to determine whether they are safe to use during pregnancy. Hence it should
not be assumed that a product is safe for use during pregnancy because it is sold over-the-
counter.nd

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