Abbreviations

Here you go

AF = Aunt Flo (menstruation/period)
AIO = All In One (nappy)
BBT = Basal Body Temperature
BCP = Birth Control Pills
BD = Baby Dance (sex)
BF = breast feeding
BFN = Big Fat Negative
BFP = Big Fat Positive
BFFP = Big Fat False Positive
BT = Blood Test
CDxx = Cycle Day
CM = Cervical Mucus
DPO = Days Post-Ovulation
EBM =Expressed breast milk
EDD = Estimated Due Date
EPT = Early Pregnancy Test
EWCM = Eggwhite Cervical Mucus (also CM)
EVAP = Evaporation Line
FF = Fertility Friend
FF = Formula Feeding
FM = Fertility Monitor
FMU = First Morning Urination (also 2MU = 2nd Morning Urination)
FRER = First Response Early Result
hCG, HCG = Human Chorionic Gonadotropin
HPT = Home Pregnancy Test
HSC = Hysteroscopy
HSG = Hysterosalpingogram
IUI = Intra-uterine Insemination
IVF = In Vitro Fertilization
LH = Luteinizing Hormone
LMP = Last Menstrual Period (cycle start date)
Lap = Laparoscopy (Key hole surgery)
LP = Luteal Phase
LPD = Luteal Phase Defect
LSP = Low Sperm Count
MC, m/c, misc. = Miscarriage
MCN = Modern Cloth Nappy
MSU = Mid Stream Urine test
O, OV = Ovulation
OB = Obstetrician
OB/GYN = Obstetrician/Gynecologist
OPK = Ovulation Predictor Kit
OSFA = One Size Fits All
PCOS = Polycystic Ovary Syndrome
PG = Pregnant
POAS = Pee on a Stick
PMT = Pre Menstral Tension
PSN = Porn Star Nipples
RE = Reproductive Endocrinologist
RPL = Recurrent Pregnancy Loss
SA = Semen Analysis
STI/STD = Sexually Transmitted Infection/Disease
TTC = Trying to Conceive
TWW / 2ww = Two week wait
US, u/s = Ultrasound
UTD = Up The Duff (pg)
UTI = Urinary Tract Infection

General chat abbreviations
AFM = As For Me
DD = Dear/Darling Daughter
DF = Dear/Darling Fiance/Fiancee
DH = Dear/Darling Husband (also Dumb Husband! )
DP = Dear/Darling Partner
DS = Dear/Darling Son
DW = Dear/Darling Wife
ETA = Edited to Add
FAQ = Frequently Asked Questions
FYI = For your Information
HTH = Hope That Helps
IMO = In My Opinion
IMHO = In My Honest/Humble Opinion
IRL = In Real Life
IYKWIM/IYGWIM = If You Know/Get What I Mean
LMAO = Laugh my ass off
LOL = Laugh Out Loud
MIA = Missing In Action
OP = Original Post/Original Poster
OT = Off Topic
OTT = Over The Top
PMSL = Pissing Myself Laughing
ROTFL = Rolling On The Floor Laughing
SH = Stupid Husbands (Cause we all have those days!)
SO = Significant Other
TJ = Threadjack
TMI = Too much information

I found it easier to learn if i printed them all out and kept them my the computer at all times

Another few:

MW = Midwife
FAA/FAW = Fertility Associates Auckland/Wellington
SAHM/SAHD = Stay at home Mum/Dad
OSFA = One size fits all (cloth nappies) - this one took me ages to work out.