Sexual And Reproductive Health Flashcards
Describe endometrial polyps
Benign outgrowths from the endometrium
Can see on transvaginal ultrasound
Usually small and asymptomatic that don’t require treatment
Symptoms include blood, pain and subfertility
Can be removed surgically without general anaesthetic
Describe fibroids and risk factors
Common Benign tumours of myometrium
Intramural (most common), submucosal (into uterus) and subserosal
Risk factors: older age, obesity, black, nulliparity
Symptoms of fibroids
Depends on type
Intramural and submucosal likely cause heavy bleeding, pain and infertility
Subserosal more likely to impede other organs and cause bladder and bowel symptoms
Heavy/painful periods, abdo pain, lower back pain, urinary frequency, constipation, painful sex
Pathology of fibroids
Firm, round, white tumour with a spiral (whorled) structure
Cells are long spindle muscle cells arranged in interlacing bundles
Management of fibroids
Asymptomatic don’t require treatment
Medications for bleeding
Ulipristal acetate or GnRH (short term) can shrink fibroids
Hysterectomy is gold standard if fertility not wanted
Resection may be possible if <4cm
Myectomy (removing it) difficult because of complicated blood supply but can be done if fertility needed
Describe adenomyosis
Endometrial tissue is found in myometrium
Typically occurs in older women (40s) who have had children, will stop after menopause
Presents with HMB and dysmenorrhea, uterus will be symmetrically enlarged and tender
Treatment = Mirena coil/ NSAIDS, hysterectomy
What HPV strains are most associated with cervical cancer?
16 and 18
What strains of HPV cause genital warts?
6 and 11
What is the precursor to cervical cancer that is asymptomatic but can be picked up on smear?
Cervical intraepithelial neoplasia (CIN) precursor to SSC (90%)
CGIN is precursor to adenocarcinoma which is harder to detect
Smear HPV positive but cytology negative, do you do a colposcopy?
No, recall in 12 months, only do colposcopy if 3 consecutive positives for HPV
Smear HPV positive, cytology positive. When do you do a colposcopy?
Low grade within 8 weeks
High grade within 4 weeks
Describe how you would visualise abnormal cells in a colposcopy
Abnormal cells contain more protein and less glycogen than normal epithelium
Apply acetic acid, abnormal cells appear white
Symptoms of cervical cancer
Post coital bleeding Foul smelling, watery discharged Intermenstrual bleeding Pelvic pain Menorrhagia
If advanced: backache, leg pain, haematuria, weight loss, anaemia, bowel changes
Describe HPV vaccination
Girls and boys ages 12-13 as 2 doses 6 months apart
Quadrivalent for HPV types 6, 11, 16 and 18
70% protection against cervical cancer
What are the most common types of cancer in cervix and uterus
In cervix, it’s squamous cell carcinoma
In uterus, it’s adenocarcinoma
What week is the cut off for a miscarriage and stillborn?
Before 24 weeks = miscarriage
After 24 weeks = stillborn
Describe the differences between a threatened miscarriage, an incomplete miscarriage and a complete miscarriage
Threatened = bleeding with closed cervix Incomplete = blood and products located at open cervix Complete = cervix is closed, all products have passed through into the vagina
Describe type 1 ovulation disorder
- Hypothalamic pituitary failure, not producing enough GnRH -> low LH and FSH
Causes, stress, low BMI, too much exercise, head trauma, drugs
Treatment is with modifiable factors and pulsatile GnRH pump or daily injections of LH and FSH
Describe type 2 ovulation disorder and treatment
Mostly PCOS
Hormone levels mostly normal or maybe high
Associated with obesity, T2DM, hypertension
Treatment 1st line is Clomifene on day 2-6 of cycle, or Letrozole
2nd line is GnRH injections but risks multiple pregnancies
3rd line is laparoscopic ovarian diathermy which risks ovarian damage
Describe type 3 ovulation disorder
Essentially menopause before age 40
LH and FSH raised but low oestrogens
Causes, Turner syndrome, chemo/radiotherapy, autoimmune
Cannot stimulate egg production
Treat with combined HRT and look into egg donor/ other child options
In pregnancy with does Human Placental Lactogen / human chorionic somatomammotropin (HPL/HCS) do?
Produced from week 5
Helps with growth - causes protein tissue formation
Decreases maternal insulin sensitivity so baby gets more glucose
Breast development
What does progesterone do during pregnancy?
Rises throughout
Development of decidual cells
Decreases uterus contractility
Helps prepare for lactation?
What do oestrogens do during pregnancy?
Rise throughout
Enlargement of uterus, breasts, relaxes ligaments to prepare for labour
What does Human Chorionic Gonadotrophin (HCG) do during pregnancy?
Prevents involution of corpus luteum
Sex development
Levels double every 48hrs in early pregnancy then fall at week 12-14
What cardiovascular changes happen during pregnancy?
Increase in HR by about 10-20bpm and rise in CO (30-50% more)
BP drops in 2nd trimester (approx. 15mmHg) then rises again
ECG changes, murmurs, extra heart sounds are all normal
All are exaggerated with multiple pregnancies
Describe pre-eclampsia
After 20 weeks of pregnancy, characterised by hypertension, proteinuria and oedema
Multi-system disease with diffuse vascular endothelial dysfunction
Stage 1 = abnormal placental perfusion cos of trophoblast invasion
Stage 2 = mum responds causing systemic disease
Symptoms of Pre-eclampsia
Hypertension
Proteinuria
Oedema
Headaches Visual disturbances Upper abdominal pain Involuntary movements N+V
What is eclampsia
Tonic clonic seizures on top of symptoms of pre-eclampsia
What is HELLP syndrome?
Crisis in pre-eclampsia
Haemolysis - cos of endothelial damage resulting in tiny thrombi which damage RBCs
Elevated liver enzymes
Low platelets
Symptoms of epigastric pain, N+V, jaundice
If over 34 weeks then deliver baby!
Broad ligament
Double layer of peritoneum separating uterus from lateral walls and floor of pelvis
Contains uterine tubes and proximal part of round ligament
Keeps uterus in midline position
Round ligament
Attaches to lateral part of uterus and the superficial tissue of perineum
Passes through DEEP inguinal ring
Is an embrylogical remnant of the gubernaculum
Why is sampled during a smear?
Squamocolumnar junction (transformation zone)
What is the nerve supply to levator ani muscles?
Sacral plexus S3, 4, 5 and pudendal S2, 3, 4
What levels do the breasts originate?
Rib level 2 - 6
What gives boobs movement separate from the pecs?
Retromammary space
Lymph supply to the breast
75% to axillary nodes leading to supraclavicular
Rest to parasternal nodes
Blood supply to breast
Medial mammary arteries from internal thoracic which is a branch of subclavian
Lateral mammary arteries from lateral thoracic artery which is a branch of axillary
Tunica vaginalis
Sac inside the scrotum that the testis and distal end of epididymis sit in
Where fluid collects with a hydrocele
Describe journey of sperm
Produced in seminiferous tubules
Pass to rete testis then head of epididymis
Epididymis becomes vas deferens
Vas deferens passes superiorly through the deep inguinal ring in the spermatic cord
Travels posteriorly over bladder and back down
Joins with duct from seminal glad to form ejaculatory duct
Left and right join together within prostate gland and drain into urethra
What helps control the temp of testis?
Dartos muscle
Describe the erectile tissue in penis
Left and right Corpus cavernosum which carries deep arteries of penis
Corpus spongiosum carries spongy urethra and expands to form glans of penis
Blood supply to penis and scrotum
Penis - Deep arteries of penis from internal pudendal from internal iliac
Scrotum - internal pudendal from internal iliac, and branches from external iliac
Pelvic diaphragm
Levator ani muscles = Puborectalis, pubococcygeus and iliococcygeus
+ Coccygeus muscle
(These are listed deep to superficial)
What type of epithelium is the nipple?
Thing, highly pigmented, keratinised stratified squamous epithelium
What happens to the breasts during the menstrual cycle?
In the luteal phase, epithelial cells increase in height and the lumina of the ducts become enlarged
There is a small amount of secretions but these are only detectable histologically
Describe fibrocystic changes to the breast
Benign
Caused by exaggerated responses to hormones
Mostly occurs in pre-menopausal women
Presents as lumpiness of the breast and is PAINFUL
Histology would show cysts with intervening fibrosis
Treatment: Rule out malignancy and reassure
Describe fibroadenoma
Commonest benign tumour of breast
Mostly young women
Presents as single small lump that is firm and mobile. PAINLESS
Histology would show connective tissue and epithelium
Treatment: Reassure, only remove if symptomatic
Describe fat necrosis of breast
Occurs due to trauma (seatbelt/surgery) or warfarin therapy
NEcrotic fat with lipid rich macrophages, giant cells and goes on to fibrosis
Can mimic carcinoma so need to rule that out
Generally goes away on its own
Describe duct ectasia of the breast
Chronic inflammatory condition associated with ectasia of ducts/cystic dilation
Often women who are peri-menopausal and smoking
Symptoms: Mostly affects sub-areolar ducts, painful, episodic changes, bloody/purulent discharge, fistulation, nipple retraction and distortion
Treatment: treat acute infections, exclude malignancy, smoking cessation, surgery if bad enough
Describe duct papilloma of the breast
Benign tumour of duct system (can happen anywhere but breast most common)
Solitary or multiple lumps, discharge from nipple which may be blood stained
Discharge will show benign epithelial cells
Treatment: Remove surgically and histologically examine as can develop cancer
What defects does a maternal rubella infection cause?
Microcephaly
Patent ductus arteriosus
Cataracts
Deafness
What maternal infection is the leading non-genetic cause for sensorineural deafness?
Cytomegalovirus
Risk higher in 1st trimester or if its primary infection
Refer to a specialist
What conditions does fetal parvovirus (slapped cheek) infection cause?
Severe anaemia Heart failure Hydrops fetalis High risk if before 20 weeks Refer to specialist
Why are pregnant women more prone to UTIs
Progesterone causes sphincters to relax
Incidence of pyelonephritis is also increased.
Describe Ductal Carcinoma in Situ (DCIS)
Cells lining the ducts show malignancy but haven’t yet invaded the stroma
The focal calcification can be detected on mammogram
Can cause Paget’s Disease of the Nipple
Describe Paget’s Disease of the Nipple
Inflammatory eczema-like changes on nipple and maybe the surrounding areola
Caused by high grade DCIS that has extended along the ducts and is now at the nipple
How would you treat DCIS and Pagets?
Surgery probably with radiotherapy afterwards
Describe Infiltrating Ductal Carcinoma
Commonest form of breast cancer
Presents as firm hard lump
Microscope will show cords of tumour cells, dense collagenous stroma and occasional acinar formation
What is the most common benign breast tumour?
Fibroadenoma
Most common type of malignant breast cancer?
Infiltrating Ductal Carcinoma
Describe infiltrating Lobular carcinoma
10% of breast cancers
Possibly multifocal and/or bilateral
Microscope will show infiltration as single files of malignant cells
Risk factors for breast cancer
Prolonged oestrogen exposure (starting early, finishing late, never been pregnant)
Age
BRCA 1 and BRCA2
Smoking
Alcohol
Lack of exercise/obesity results in increased oestrogen
Breast feeding reduces risk as it inhibits menstruation
How does receptor status effect the prognosis of breast cancers?
Check oestrogen, progesterone and HER2 receptor status
ER+ and/or PR+, HER2- have the best prognosis
HER2+ but ER- and PR- have a poorer prognosis
Triple negative cancers have the worst prognosis
How can you reduce the risk of ER+ cancers returning?
Anti-oestrogen therapy
If pre-menopausal, should given Tamoxifen for at least 5 years
Tamoxifen is an ER receptor antagonist
If post-menopausal, Aromatase inhibitors are thought to be better
What type of breast cancers would trastuzumab and herceptin treat?
HER2+ cancers
They are a monoclonal antibody
Why do mammograms take longer than other x-rays?
Low energy as high would not show breasts
Screening programme for breast cancers
Ages 50-70 every 3 years
How long after sex can a copper coil be used for contraception?
5 days
Describe Nexplanon Implant
Progesterone only
Less hormonal side effects than oral cos it secretes a low an d stable level of hormones
Can cause prolonged bleeding
Contraindication to POP
Current breast cancer
POP: pill is more than 12hrs late, what to do?
Take missed pill even if it means taking 2 pills in one day
Use other contraception for next 2 days
COCP: Missed 2 or more pills, what to do?
Take last missed pill, even if you take 2 in one day
Use extra contraception for next 7 days
May also need emergency contraception if this happened in the first week of a new pack
Desogestrel is…
The progesterone only pill (POP)
Contraindications for Depo injection?
The injections suppress oestrogen and so this can affect bone mass
- > dont give to teens who are still building bone mass
- > dont give close to menopause as theyll be losing bone mass
Contraceptives suitable for someone on anti-epileptic drugs
IUS, IUD, DMPA (injections) and barriers
2 most common clauses of Offenses against the person act that allow abortion
Clause C: 24 weeks gestational limit, risk of physical or mental health of pregnant woman and children/family
Clause E: No gestational limit, risk that child would be born with physical and mental abnormalities that they would be seriously handicapped
Medical abortion
Mifepristone (progesterone antagonist) orally, followed by Misoprostol (prostaglandin) sublingually or vaginally
Misoprostol causes the uterus to contract and expel the pregnancy
May need more misoprostol if longer gestation
Low sensitivity pregnancy test 2 weeks after (HCG level wont have fallen yet so cant use normal ones)
Pathogenesis of HIV
Infection of mucosal CD4 T helper cells and these transport virus to regional lymph nodes
-> permanent infection, virus infected CD4 cells enter blood stream
Infection is established within 3 days of entry
There is reduced circulation CD4 cells and proliferation of CD4 cells
-> reduced activation of CD8 cells
-> reduced antibody class switching
-> chronic immune activation
Definition of AIDS-defining condition
Opportunistic infection: an infection caused by a pathogen that doesn’t normally produce disease in a healthy individual
3 AIDS-defining cancers
Kaposi’s Sarcoma: vascular tumour caused by herpes virus
Non-Hodgkins Lymphoma: frequently extra-nodal, often involves the brain
Cervical Carcinoma: caused by oncogenic HPV, annual cervical screening needed
Why is ano-receptive sex more likely to spread HIV?
More lymphoid tissue in rectum
Anal sex more likely to cause microabrasions
Describe what you look for in HIV test
P24 antigen - not positive until 6 weeks of infection
Antibody not positive until 3 months after infection
-> can have HIV and test negative
Treatment for candida infection
‘Azoles’
Topical clotrimazole pessary or cream (can get over-the-counter)
Or oral fluconazole
Non-albicans (5%) are more likely to be resistant to azoles, try topical nystatin
These treatments can damage latex condoms and stop spermicide from working so ned alternative contraceptives for 5 days after use
Symptoms of candida infection
Vulval itching/burning Thick, white, vaginal discharge External dysuria Superficial dyspareunia White curdy plaques seen on vaginal walls with speculum examination
What does gonorrhoea look like microscopically?
Gram negative (pink) Diplococcus
Symptoms of gonorrhoea in men and women
Men: Anterior urethritis with purulent discharge and dysuria
Women: increased vaginal discharge, dysuria, post-coital or intermenstrual bleeding and lower abdo pain
Test for gonorrhoea and where to take swabs
NAAT (nucleic acid amplification tests) have better sensitivity than culture
Need to culture before giving any treatment cos antimicrobial resistance is really common
Men: first void urine or urethral swabs. MSM maybe need rectal or pharyngeal swabs
Women: vulvo-vaginal or endocervix swabs (FVU not as sensitive)
Treatment for gonorrhoea
Need to culture and refer to SARH before any treatment given
IM ceftriazone possibly with azithromycin
Need follow-up “test of cure”
Incubation period of gonorrhoea
Men: 2-5 days
Women: 2-14 days
Most common STI in UK
Chlamydia
Incubation period of chlamydia
7-21 days
Symptoms of chlamydia in men and women
Women: increased vaginal discharge, dysuria, post-coital or intermenstrual bleeding
Men: urethritis with milky discharge and dysuria
Test and swab area for chlamydia
NAAT test of choice
Men: first void urine or urethral swab
Women: vulvovaginal or endocervix swabs
Treatment of chlamydia
7 days doxycycline, if cant take then use azithromycin instead
Recommend no sex for a week after treatment to prevent infecting others or re-infecting yourself
Symptoms of bacterial vaginosis
Increased vaginal discharge with fishy odour and creamy texture, may be frothy
Raised vaginal pH (>4.5)
How to diagnose bacterial vaginosis
Can be clinical diagnosis with symptoms and raised vaginal pH
Most accurate is by microscopy (clue cells on gram stained vaginal fluid)
Bacterial vaginosis under microscope
Gram stained vaginal fluid will have clue cells
Clue cells are epithelial cells that have bacteria stuck inside them, usually gardnerella vaginalis
Treatment of bacterial vaginosis
Metronidazole
Test and swab for genital herpes
PCR test by swabbing deroofed blister
Serology igG only tells you if a person has ever been in contact with HSV (which most people have been)
Treatment of genital herpes
Oral aciclovir
If painful can consider topical lidocaine, saline bathing or analgesia
Test for syphilis
PCR tests or serological to look at antibodies in blood test
Doesnt gram stain and cant be grown
Can diagnose with dark field microscopy
Treatment for syphilis
Long-acting penicillin injections
Even if someone is allergic you need to desensitize them first
Nothing else works as well
Symptoms of primary stage of syphilis infection
10-90 days after infection (usually 3 weeks) Painless ulcers (primary chancre) that heal within 2-6 weeks, may go unnoticed
Symptoms of secondary stage of syphilis infection
6-10 weeks after primary chancre Snail track ulcers Red, non-itchy rash on palms and soles Malaise Generalised Lymphadenopathy Anterior uveitis Fever Sore throat
Contraindications to HRT
History of breast cancer, coronary artery disease, TIA or stroke
Unexplained vaginal bleeding
Active liver disease
Who gets what HRT?
If person has a uterus and no coil then give oestrogen and progesterone
If they have had a hysterectomy or have a mirena coil then only need to give oestrogen
Need progesterone with the oestrogen to stop endometrial hyperplasia that could lead to cancer
Symptoms and treatment of vulvo-vaginal atrophy
Thinning, drying and inflammation of vaginal walls caused by lack of oestrogen Dryness Soreness Dyspareunia Urge incontinence
Treat with topical oestrogen which has little risks and can be used as often as needed
What is lichen sclerosis and who tends to get it?
Inflammatory, scarring dermatitis of ano-genital skin
Usually pre-pubertal girls or post-menopausal women, can occur in males but rare
Linked with other autoimmune conditions
80% affected have extra cellular matrix protein-1 (ECM-1) antibodies
Symptoms of lichen sclerosis
Itch Pain Dyspareunia Constipation White papules and plaques on external skin Ecchymosis (bruising) Erosions and fissures
Can develop into vulval SCC
Treatment of lichen sclerosis
Genital skin care advice/emollients
Super potent topical steroid with a step-down regime
Which lymph nodes does ovarian cancer drain to first?
Para-aortic / lumbar
Which lymph nodes does cervical cancer go to first?
Pelvic lymph nodes /internal iliac arteries
What do cells of endothelium look like?
Pseudostratified columnar with tubular glands
Cells of cervix
Stratified squamous cells
Cells of ovary
Cuboidal cells
Cells of vagina
Glycogen-containing stratified squamous cells
Cells of Fallopian tubes
Columnar ciliated cells
What lymph nodes do the testes drain to?
Para-aortic / lumbar nodes
What’s the primary method of action of the COCP?
Prevents ovulation
What’s the primary mode of action of the POP?
Thickens cervical mucus
Unless it’s the desogestrel then it prevents ovulation
What’s the primary mode of action of the depo injection?
Inhibits ovulation
Also thickens cervical mucus
What’s the primary mode of action of the rod (etonogestrel)?
Prevents ovulation
Also thickens cervical mucus
What’s the primary mode of action of the interuterine device (copper coil?)?
Decreases sperm motility and survival
What’s the primary mode of action of the interuterine system (hormonal coil)?
Prevents endometrial proliferation
Also, thickens cervical mucus
How does HPV lead to cancer?
It produces two proteins that inhibit the tumour suppressor genes, p53 and pRb
What staging system is used for cervical cancer?
FIGO (international federation of gynaecology and obstetrics)
Stage 1: just cervix
Stage 2: in uterus or upper 2/3 of vagina
Stage 3: pelvic wall or lower 1/3 of vagina
Stage 4: invading bladder, rectum etc.
What do “signet ring’ cells on ovarian histology mean
It is a metastasis from somewhere else = Krukenberg tumour
What structure is an ovarian mass likely to affect?
Obturator nerve
It passes lateral to the ovaries
Causes referred hip or groin pain
Investigation for ovarian cancer before referral?
CA125 blood test (>35IU/ml is significant)
What is bacterial vaginosis?
Lack of lactobacilli in the vagina. This is ‘good bacteria’ that produces lactic acid that makes the pH <4.5
Lack of this bacteria makes the vagina more alkaline which allows anaerobic bacteria to multiply
Most commonly, Gardnerella vaginalis
What will microscopy of PID look like
It may have pus cells. It doesnt necessarily mean it is PID but the absence of pus cells will rule out PID
Treatment for PID
Outpatient: Oflaxacin and metronidazole for 2 weeks
Inpatient: IV ceftriaxone, IV metronidazole and PO doxycycline (can sub doxy with IV azithromycin)
Inpatient allergic to penicillin: IV clindamycin and IV gentamicin with a step down to oral doxycycline and metronidazole
What does a “strawberry cervix” indicate?
Trichomoniasis
Causes tiny haemorrhages across the cervix from inflammation
Symptoms of trichomonas vaginalis
Discharge: frothy, yellow-green, may smell fishy Itching Dysuris Dyspareunia Balanitis (glans inflammation) Raised vaginal pH
Swab and treatment for trichomonas
Swab should be from the posterior fornix but can take a low vaginal swab
Men should have a urethral swab or first-catch urine
Treat with metronidazole and refer to GUM
What is Sheehan Syndrome
After a postpartum haemorrhage or shock, there could have been lack of blood flow to parts of the brain causing necrosis of the anterior pituitary.
Presents with lack of pituitary ly noticeable by lack of lactation.
What pathogen causes syphilis?
Treponema pallidum
Medical name for foreskin
Prepuce
Where does lymph from the scrotum and penis drain to?
Superficial inguinal lymph nodes
Treatment for mastitis
Oral flucloxacillin
Treatment for nipple thrush in a breastfeeding mother?
Topical anti fungal cream (miconazole) for breasts and for baby’s mouth (though this is an off-license use)
Drug for emergency contraception
Ullipristal acetate (EllaOne)
Can be taken within 120hrs
Selective-progesterone receptor modulator
Inhibits ovulation
How to diagnose if suspected gestational diabetes
Oral glucose tolerance test
Describe the combined test for Down’s syndrome screening
Between 11 and 14 weeks gestation
Ultrasound - Nuchal thickness >6mm
Maternal blood tests - high beta-HCG and low PAPPA
Describe the triple test for Down’s syndrome screening
Between 14 and 20 weeks gestation Maternal blood tests only High beta-HCG Low alpha-feta protein (AFP) Low serum oestriol
Describe chorionic villus sampling and amniocentesis
Fetal cells used for Karyotyping
CVS uses ultrasound-guided biopsy of placental tissue
Done before 15 weeks
Amniocentesis uses ultrasound-guided aspiration of amniotic fluid using a needle and syringe.
Done in later pregnancy once there is enough amniotic fluid to make it safer.
Describe non-invasive prenatal testing
Maternal blood test that will contain fragments of DNA, some of which come from placental tissue and represent fetal DNA
How to manage hypothyroidism in pregnancy
Levothyroxine dose needs to be increased by 30-50% because it can cross the placenta and provide thyroid hormone to the foetus.
Titrate for a low-normal TSH level
What hypertension medications should be stopped during pregnancy?
ACEi
ARBs
Thiazide diuretics e.g. indapamide
Anti-epileptic medications that are safe in pregnancy
Lamotrigine
Levetiracetam
Carbamazepine
DONT use sodium valproate as it causes neural tube defects and dont use phenytoin as it causes cleft lip and palate
What immunosuppressants are safe during pregnancy?
Hydroxychloroquine
Sulfasalazine
Corticosteroids
DONT use methotrexate
Why are NSAIDS contraindicated for pregnancy
They block prostaglandins that are needed
Prostaglandins maintain the ductus arteriosus and soften the cervix and stimulate contractions at time of delivery
If used in the 3rd trimester they can cause premature closure of the ductus arteriosus and delay labour
Antibiotics for a UTI during pregnancy
7 days of antibiotics
Nitrofurantoin - avoid in 1st trimester - neonatal haemolysis
Amoxicillin if you know sensitivities
Cefelexin
NOT trimethoprim - folate antagonist
Placenta Praevia
Placenta is over the cervical os
Vasa praevia
Fetal vessels travel over the cervical os
Placenta Accreta
The placenta implants deeper past the endometrium and is hard to separate after delivery of the baby
