Lecture
Drugs in Pregnancy – November 14, 2002
By: Joanne C.Y. Chan
Introduction
• Limited # of drugs that can negatively affect a patient’s pregnancy
• 30% of pregnancies go on to have spontaneous abortions/miscarriages before women knows she is pregnant
• 15% go on to have miscarriages after women has missed a period
• 3% of all pregnancies have major congenital anomaly no matter what
o Material exposure to drugs or environmental chemicals are responsible to 4-6% of abnormalities of the 3%
Teratogenic Drugs
• If any meds given after vulnerable period (after fetus is formed) won’t cause structural abnormalities
• there is a fixed amount of time to be concerned about structural abnormalities due to a drug
Hormonal Medications
1) Oral Contraceptives
• no relationship with 1st trimester OCP use and congenital abnormalities ( can reassure the patient 100% that no harm will be done to baby
2) Danazol/Androgenic Meds
• If taken during pregnancy, can cause clitoral enlargement in fetus if you take it < 13 weeks
3) DES (Diethyl ?)
• associated with clear cell cancer of vagina and cervix
• Uterine abnormality in daughter’s who’s mothers took DES while pregnant
• Abnormality in male children (cryptorchism – problems with testes)
Drugs that should NEVER be given to a Pregnant Women
1) Warfarin
• In Canada this is NEVER used in pregnant women
• In Europe, they still use it b/c they think its “safe”
• 25% of fetuses develop a congenital abnormality if mom takes it in 1st trimester
• Critical time period = 6 – 9 weeks
• Fetal Warfarin Syndrome Symptoms
o Hypoplastic nose
o Epiphyseal stipling
o Optic atrophy
o Small head
o Intrauterine growth retardation
o Neurologic abnormality (mental retardation)
Exam Hint: She said that the FWSS would be a good exam question
Alternative to Warfarin
• If mom is on W b/c of a clotting abnormality, can switch to heparin or LMWH, which are both safe in pregnancy
2) Anti-Convulsants
• Significant (ed risk of neural tube defects
|Carbomezipine |1% risk above baseline risk |
|Valproic Acid |2% risk above baseline risk |
|Phenytoin |10% risk of above baseline risk |
• Carbomezipine is the DOC for a pregnant women at risk of seizures b/c it is associated with the lowest risk
• You would never use Phenytoin (high risk)
• Fetal Hydratoin Syndrome
o Cradle, facial and limb deformities
o Mental deficiencies
|Folic acid supplementation|4 mg/day in pregnancy |Needed for all epileptics |
| | |Needed to prevent neural tube defects |
|Vitamin K supplementation |20 mg/d for 2 weeks before estimated |Needed for patients on Carbomezipine, otherwise Fetal |
| |delivery date |Coagulopathy |
Aside
• Benzodiazepines are safe
• In pregnancy, you always have to consider that there are 2 patients ( must consider BOTH the mother’s and the fetus’s well-being
• Often need to weigh risk/benefit ratio of both of
3) Lithium
• 0.5% risk of Ebstein’s anomaly (serious cardiac anomaly)
• if you take it in late pregnancy, can get:
o transient lithium toxicity in fetus
4) Isotretinioin
• Retinoids
o Vitamin A
▪ No (ed risk associated with it
▪ OK to use
• Tretinoin
• Most potent drug that we know about
• 35-50% exposed (taken anytime in pregnancy) will have abnormalities including:
o (ed risk of marriage
o risk of heart disease
o deafness
o cleft lip/palate
o small ears and eyes
• if a female is trying to get pregnant, don’t take it
• Topical tretinoin is safe in pregnancy
In general,
• most drugs will cause a problem early on in pregnancy, therefore, the first 12 weeks of pregnancy is CRUCIAL time NOT to take these medications
5) Thalidomide
• If the fetus is exposed to this, there is a 20-25% risk of the following:
o Severe limb abnormalities
o General heart disease
o Kidney problems
o Stomach problems (e.g duodenal atresia)
o Hearing problems
o Hernias
• Once exposed, the risk of limb defects is 80%
• NEVER take it anytime during pregnancy
6) Misoprostol (Cytotec ®)
• 1 – 2 % above baseline risk of Moebius seqius (sp?)
• congenital cardiac abnormalitiy and facial abnormalities - very rare defect
• used as an abortefacient (e.g. used to abort fetus in 1st trimester if fetus has a genetic abnormality or if personal has had a miscarriage)
• has prostaglandin ( makes uterus contract, induces “labor”
• Varying doses (400-800 ug) ( can give vaginally or P.O.
o 800 ug PV – give 12 hours apart for 2 doses
o very effective
• In Canada, trials underway about inducing labor term
• Used for cervical softening before procedures such as: D & C, hystroscopy
o Softens it up by making uterus contract
o Decreases risk of perforating
o Giving it vaginally
• Experiments underway for using this in post-partum hemorrhage
o Makes uterus contract
• Term studies use lower doses (50 ug)
Giving Misoprostol after Miscarriage
• except pain/cramps (putting them in “labor”)– Rx Tylenol #3 (analgesia)
• after taking Misoprostol, the following occurs:
o development of menstrual cramps (get more intense)
o short period with extreme bleeding
o abnormal dead fetus is “passed”
▪ If this occurs < 10 wks – can’t tell that it is a baby, as it appears like grayish tissue among a blood clot
o a women will continue to bleed after passing the dead fetus, but her bleeding and cramps will (
• If she still has a heavy period (“heavy” = you have to change your pad every hour) – send them to ER
• Variable time effect – a few hours, some have to repeat dose to get effect
• if pass fetus and bleeding stops – don’t need to take the 2nd dose
7) Alcohol
• Fetal Alcohol Syndrome
o Microencephaly
o Heart defects
o Facial abnormalities
o Mental retardation
• You need to intake > 3 oz/day of alcohol every day of your pregnancy to get this (you have to be a severe alcoholic)
• In pregnancy, you can take most things in moderation, and it will be ok.
• 1 glass of wine is safe
8) Tobacco
• Tobacco is now illegal to sell in the pharmacy, you can only buy them in the grocery store
• Associated with:
o Miscarriage
o Low birth weight
o Placenta abruption (placenta separates from the uterus prematurely and cuts off circulation to the baby)
• If a women stops smoking in the last 4 months of her pregnancy, the risk of having a low birth weight baby is the same as people who have been non-smokers for life
• Can smoke up to 20 weeks with no problem
9) Marijuana
• Has been shown to be teratogenic in animals only, no human studies
Other Drugs to Avoid
1) ACE-Inhibitors
• cause fetal damage
2) Tetracycline
• can cause bone abnormalities and yellow teeth
3) NSAIDS
• can cause:
o premature closure of the ductus arteriosis (doesn’t allow oxygenated blood to the fetus)
o fetal kidney problems
• care with long term NSAID use
• safe to take 1 – 2 tablets, but better options available, that are safe:
o Tylenol (100% safe)
o Codeine
• In general, there are often better options available
4) Sulfonamides
• avoid when near term
5) Methotrexate
• avoid at all costs
• MTX is used to abort pregnancy
• For Etopic Pregnancy
o for patients that are stable and don’t want surgery, they use MTX to kill etopi
• Some people are experimenting with this for abortion rather than surgical abortion
o They use MTX first, and then use Misoprostol
Infections that are Dangerous in Pregnancy
1) Varicella (Chicken Pox)
• < 13th week of pregnancy, there is a 1% risk of congenital varicella if exposed
• > 13th week of pregnancy, this increases to a 2% risk if exposed
• this is very severe syndrome, as it can cause:
o mental retardation
o limb and eye abnormalities
• no documented cases of congenital varciella syndrome with herpes zoster
Cases
• If women is exposed to chicken pox and..
o 1) HAD it before = she’s ok, don’t need to do anything
o 2) NEVER had it before:
▪ She needs to go see MD/walk-in clinic and get tests to see if she is sero-positive (+) or sero-negative (-)
• If sero-positive (+) = she is ok, she is not at risk
• If sero-negative (-) = give immunoglobin BC?
2) Rubella
• Part of the routine prenatal screening is for rubella
• Screening is performed in the form of a blood test
• Want to know if you are immune to it, if not, need to get vaccinated
• If this is transmitted in:
|First 10 weeks of pregnancy |100% that baby Is infected – can get heart defect, deafness, mental retardation|
|13 – 16th weeks of pregnancy |only deafness has been reported |
|> 20th week of pregnancy |no abnormalities |
Exam hint = she mentioned this would be a good exam question
Uterus Size Changes in Pregnancy
• different weeks in pregnancy correspond with different uterus sizes
|Normal Uterus |About the size of a fist, or a small plum |
|At 10-12 weeks |Uterus comes out of the pelvis, can feel it abdominally |
| |About the size of an orange |
|At 20 weeks |Uterus is felt at the belly button |
|At 36 weeks |Uterus is up to the rib cage |
Right after delivery, the uterus goes back to the belly button, and after 10 days, should be back at the pelvis and you shouldn’t be able to feel it.
Pre-Natal Vitamins
• can use ANY pre-natal vitamin, doesn’t have to be Materna
• these do NOT replace a well-balanced diet
• still need a well-balanced, Canada Food Guide diet
• “eating for 2” is a myth – you are only eating for ONE
Iron (Fe)
• need 30 mg elemental Fe/day in pregnancy
• nausea/vomiting in first 3-4 months in pregnancy which is aggravated by Fe
o Option 1 = It is ok to NOT take Fe during the first 12 weeks
o Option 2 = take Fe at BEDTIME (so nausea occurs while you sleep)
Vitamin C
• need 20% increase during pregnancy – use 70 mg/d
Folic Acid
• ( neural tube defects
o Spina epifida = failure to close neural tube at 26-28 days of gestation – occurs very early on, therefore it is important to take this BEFORE you get pregnant
• often found in multi-vitamin
• it is very important to take this medication right before due date
• should recommend to anyone in child-bearing age who may want to get pregnant
|For general population |0.4 mg/d X 1 month prior to conception |
|For high risk (i.e. previous infant w/ spina epifida, or mother|4 mg/d X 3 months prior to conception |
|has epilepsy) | |
Random Questions
• Lower C-section (go transversely in the lower part of the uterus)
o CAN potentially have vaginal delivery afterwards (not dangerous)
o 2% risk of rupturing uterus (mom and baby can die from this) if you had a lower –C section
• Classically C-section (go up and down uterus) or previous surgery involving cavity (removal of fibroid)
o Not eligible for a eligible for a vaginal delivery
o Don’t want to belabor that scar b/c the risk of rupture increases a lot (4-8%)
• Cold C-Section
o Had a C-section b/c you had breached baby, twins, patient wasn’t allowed to go into labor
o Chances to have a successful vaginal delivery is the same as someone who has NEVER had a C-section
• If you had a C-section b/c you previous tried labor (e.g. for 18 hours), would’nt recommend you do vaginal delivery.
• 75% of V-backs (vaginal birth after C-section) will have vaginal delivery
How long do you bleed?
• It is variable, could be 5-7 days you have heavy bright red bleeding, then similar to a regular period, then brownish, old blood, then a yellow discharge – ends in 6 weeks
• heavy bleeding stops in a 1-2 weeks
Intercourse safe in pregnancy?
• perfectly safe to have sex during pregnancy (encourage right before pregnancy)
Detecting twins
• at regular MD visits, they should be measuring the size of the abdomen, which should correlate to the number of weeks into pregnancy
• So between 20-36 weeks, size of abdomen should ( 1 cm/week (e.g. at 23 wk, should measure roughly 23 cm)
o E.g. at 31 weeks, if you measure 39 cm, may be indicative of twins
• Usually ultrasound is used
Weight gain
• Usually patients gain 25-35 lbs during pregnancy
• Obese patients gain less weight, thinner patients tend to gain more weight
• Don’t try to lose weight during pregnancy
• Generally lose around 11 lbs after pregnancy, and you have to lose the right of the weight by exercise
• Metabolic changes that occur during pregnancy
• Those who aren’t breastfeeding – takes a lot longer to lose weight
Common Complaints in Pregnancy
1) Nausea/Vomiting
• most serious between 6-13 weeks (majority will get better after this time)
• 1st line treatment:
o a) Adjust diet – smaller more frequent meals,
▪ dry bland foods
▪ separate solids from liquids
▪ if this method doesn’t work by itself, go to b)
o b) Gravol – safe, very effective, can take P.O. or rectally
▪ no RCTs, but long term evidence that show there are no contraindications.
▪ Safe all the way through pregnancy, but we don’t give it all the way through b/c it makes them feel tired.
▪ Good for needed it the “odd” time
o c) Dicleptin – longer term Tx’s, can be used for entire pregnancy
▪ give according to patient Sx
▪ max 4/day – typical dosing regimen – 1 @ AM, 1 @ Noon, 2 @ Bedtime
▪ can stop at 14 weeks and see how they feel
2) Constipation
• During pregnancy, you get a lot of smooth muscle relaxation – uterus grows and compresses bowels
• exacerbated by Fe and vitamins taken during pregnancy
Options:
o 1) ( Fiber
o 2) Metamucil/Protium or Stool softeners (want stools soft, to prevent hemorrhoids)
3) Hemorrhoids
• uterus obstructs venous return in all veins – including rectal vein
• thus you get hemorrhoids b/c of the increased pressure
• they get worse as pregnancy progresses
Options
o 1) Stool softeners – can give any
o 2) For Sx relief - use Anusol HC or Anusol Cream – safe in pregnancy
• generally, hemorrhoids improve after pregnancy (go away spontaneously)
• Cortisone and steroids are safe in pregnancy (e.g. inhaled steroids, oral steroids, often used for rash)
4) Heartburn
• uterus pushes up the stomach and esophagus and compresses it
• smooth muscle relaxation causes lower esophageal sphincter to not close properly
Options
o 1) Change diet – avoid spicy foods or things that aggravate it, avoid lying down after eating. This doesn’t work very well
o 2) Antacid (Maalox, Zantac, or Tums (has Ca+)) – for patients with bad heartburn, liquid formulation may be more effective than tablet
• don’t recommend Pepto-Bismol b/c better options are available
5) Yeast Infection
• 30-40% occurrence in pregnant women
• no danger to fetus when you have yeast infection
• toward end of term (week 35) – avoid putting creams/tablets inside the vagina, but put it around on the outside (worry that if you rupture membrane, you would have the cream/tablets lingering around)
• before end of term, can use cream/tablet inside vagina
• can’t use Diflucan, is contraindicated
Option
o only use topical azoles
o 1 day Tx – don’t use this as patients will relapse – recommend 3 or 7 day Tx
6) Headaches
Options
o DOC = Tylenol – safe in pregnancy
o Codeine – safe in pregnancy
o Morphine/demoral – for severe pain – safe
▪ Don’t give close to delivery b/c it may ( fetus respiration
• AVOID ASA/NSAIDS b/c they can cause:
o Premature closure of ductus arteriosis
o Kidney problems
o Bleeding problems at end of pregnancy
• Exceptions
o 1) Sometimes women on 81 mg/d ASA b/c of hypercoagulable state (thrombophila) that may predispose them to clotting, but never had documented clot so not on heparin
o 2) Infertility patients on low dose ASA to prevent miscarriage or pre-term labor
▪ advise patients to STOP low-dose ASA @ 36 weeks
7) Cough and Cold
• OTC meds are generally safe AFTER 1st trimester (12 weeks)
• Tell patients to use drowsy formulations b/c there are more studies done on them
• Try to avoid preps with ASA and NSAID in them
Options
o Vicks vapor rub
o Lozenges
o Pseudoephedrine – avoid if you can, probably ok after 1st trimester
o B2-agonist and steroids - use if you have prolonged cough or refractory asthma can use
• If unsure about anything – call Mother Risk – have lots of EP info
Antibiotics
• most are safe
• stay away from tetracycline, sulfa, quinolones (avoid in breastfeeding)
• quinolones = controversial topic, animal studies showed grey matter problems, therefore don’t use 1st line
Choice of Antibiotic
UTI
• asymptomatic bacteruria (2-7% occurrence in pregnant women)
• 25% of patients with asymptomatic bacteruria go on to develop symptoms
• big concern of UTI is that it puts you at risk of preterm labor
o 1st line – Nitrofurantoin
o Amoxicillin-Clavulin
o Macrobid ®
• 30% will fail on any Tx regimen
• Duration = 5-7 days (as opposed to 3-days)
Cardiac Prophylaxis
• American Heart Association - Tx all intermediate - high risk groups during high risk procedures (i.e. labor delivery)
• ACOG – said to use prophylaxis all women with any cardiac problems
• E.g. Patients with mitral valve prolapse with NO regurgitation – considered LOW RISK
o Prophylaxis is given only during labor delivery (ampilcillin and gentamicin)
• High risk = any women with cardiac problems
• Prevents 90% of infections
• Mostly for vaginal deliveries (infection during passage through vagina)
• Prophylaxis given only during labor
Group B Streptococcus
• 15-20% of women carry this vagina or rectum
• part of your normal flora
• Guidelines regarding Tx are always changing
• 1) Base Tx on risk factors
o Risk factors:
▪ preterm labor before 37 completed weeks of pregnancy
▪ ruptured membranes over 18 hours (break water but don’t go into labor)
▪ a previous infant who has been affect by Group B Strep
▪ temperature
o therefore, Tx if ANY RF are present
• 2) Screen everyone by obtaining a culture
o If culture is (-) – ruptured X 24 hours ( Don’t Tx
o If culture is (+) – Treat
• Give Penicillin G + Ampicillin IV
o Use clindamycin if allergic
• Risk is to newborn, not to mother
• Two types of infection
o 1) Early onset disease immediately after birth, usually 6-12 hours
▪ 25% mortality rate
o 2) Late onset disease occurs > 1 wk after birth
▪ usually manifests as meningitis
Drugs during Induction of Labor
• before labor, want to ripen their cervix (gets cervix ready for labor and delivery)
• typically, your cervix is usually 3-4 cm long and hard as a rock
• you need it to be shortened, and dilated
1) PGE2 – various formulations
• gel that you put in vagina (1-2 mg)
• gel that you put in cervix (0.5 mg)
• New insert called Servedil -10 mg that is CR (0.3 mg/hr)
o It has a long string attached to it for easy removal if big long uterus contraction is cutting off circulation to the baby.
• Side Effect – uterine hyperstimulation (5%) – remove as much of PG as possible (try to flush out gel – not easy or effective), or can give Salbutomol or Terbutaline (stops contraction)
2) Oxytocin
• uterine response to this depends on gestational age (( myometrial receptors as you age)
• t ½ = 5 minutes, response within 3-5 minutes
• Goal is to have 3-5 contractions every 10 minutes, and you don’t want them to last more than 1 minute
• Dosing
o Usually 10-20 U of oxytocin in a liter of normal saline
o Start at 1-2 milli units/ minute, and increase by 1-2 milli units every 20-30 minutes until good contractions
• SE = uterine hyperstimulation seen as:
o > 5 contractions in 10 minutes,
o or contractions < 2 minutes apart
o or contractions that last for > 1 minute
o Risk of this is Fetal Distress - uterus squeezes down and the baby is not getting O2
• At higher doses (45 milliunits/minute) – can get Anti-diuretic effect and water intoxification
Hypertension in Pregnancy
• Pre- Eclampsia = transient pregnancy-induced hypertension
o These are patients who have never had high BP before 20 weeks of pregnancy, and they develop it after 20 weeks and it is not associated with other Sx
o associated with proteinuria
• Essential or Chronic Hypertension = developed it > 20 weeks
• can get pre-eclampsia superimposed onto chronic HTN
o very common that people with underlying HTN will develop Sx consistent with pre-clampsia such as proteinuria, headache, visual disturbances and gastric pain.
Treatment
• Doesn’t affect maternal outcome
• Benefits fetus
• Low dose ASA – low dose prevents preeclapmsia
• DOC = methyldopa
• Labetolol (blocks ( and (), recent RCT shows that it may be better than methyldopa,
• Hydralazine 5 mg IV for emergency use (relaxes smooth muscle)
• MgSO4 – give IV, bolus 4g, then run 1-2 g/hr
o Give to ( seizure threshold
o Pre-eclampsia can go onto eclampsia, which is a full-blown seizure
• In emergency situation = don’t want to ( blood flow too quickly, b/c the first place it will cut circulation is the placenta
Avoid:
• Calcium Channel Blockers in 1st trimester (only animal study shown teratogenic) – 2nd /3rd line
• Diuretics
• ACE-inhibitors (contra-indicated)
Post Partum Depression
• Up to 15% occurrence
• very big concern
• refer to see psychiatrist
• can use almost any anti-depressant during pregnancy and breastfeeding (SSRI)
................
................
In order to avoid copyright disputes, this page is only a partial summary.
To fulfill the demand for quickly locating and searching documents.
It is intelligent file search solution for home and business.
Related searches
- marketing management pdf lecture notes
- strategic management lecture notes pdf
- strategic management lecture notes
- philosophy 101 lecture notes
- philosophy lecture notes
- philosophy of education lecture notes
- financial management lecture notes
- financial management lecture notes pdf
- business management lecture notes
- introduction to philosophy lecture notes
- business management lecture notes pdf
- introduction to management lecture notes