6. What is Coasting?
• Withholding gonadotropins with continuation of agonist or
antagonist
• Drug holiday/ no stimulation
7. Principle
• Withholding Gonadotropins
• Apoptosis of small & medium follicles, larger follicles
continue to grow
• Lesser granulosa cell population
• Reduce release of Vascular Endothelial Growth Factor-VEGF
/vasoactive substances
• Lesser chance of OHSS
8. Serum E2 during coasting
• Classically 1st day of coasting E2 increases
• Start falling gradually after 1.7days
9. When to start…….?
Three factors
• Serum estradiol level(reflects the functional granulosa cell
population)
• Number of follicles (predicts potential for further granulosa
cell proliferation and rise in E2)
• Diameter of leading follicle
10. Coasting
Types
• Early coasting :
When growing follicles of intermediate size 12 -15 mm
• Late coasting:
Growing follicle>15mm
Larger follicles less dependent on FSH
12. Coasting …….
• Reduces severe OHSS
• Reduces /eliminates cycle cancellation
• Reduces cost of therapy
• More chances of fresh transfer
• Thus offers best chance in index cycle
• Reduces distress of cancellation , OHSS and
cryopreservation of all embryos
17. Early and late coasting
Chen Chao et al ,fert sterl 2003
18. Coasting in PCOS when E2 level >1500 but
<3000pg/ml
(Egbase et al, human reprod 2002)
E2 on coasting D1 1943±693
E2 on coasting D2 2526±1063
E2 on coasting D3 2169±9753.6
No of follicles 25.2±4.1
No of oocytes retrieved 16.5±3.6
Fertilization rate 74%
Cleavage rate 88%
No of embryo transferred 2.4±0.2
Clinical pregnancy rate 45%
Severe OHSS nil
All pts PCOS with high BMI
23. Antagonist coasting
• Long protocol with hyper-stimulation can be coasted with
antagonist switching resulting in rapid fall in E2
• Mean coasting days were significantly less in antag gp(1.74 vs
2.82,p value<0.0001)
• No significant difference in clinical pregnancy rate
(Aboulgar et al 2011, fert sterl)
25. Coasting and endometrial receptivity
V. Ifaza ,Garcia et al, hum rep, 2002
• Coasting might impair endometrial receptivity
• Prolonged coasting associated with luteinization of
endometrium
• Poor endometrial receptivity d/t high E2 level
• Thus embryo quality and implantation potential is best
studied in recipients having donor oocytes from coasted vs
non coasted donors
26. Embryo Quality in Coasting
recipient Coasted donor Non coasted donor P value
M II oocytes 6.9 7.4 ns
Fertilization rate 80.7% 83.3% ns
Cleavage rate 92% 96% ns
Embryos transferred/pt 2.6 2.9 ns
Implantion rate 22 27.7 ns
Preg rate 52.9% 54.5% ns
When coasted more than four days implantation rate was significantly low in
coasted donor group probably due to bad quality oocytes /embryos
Implantation rate 30.5 % vs 11.3% (p value<0.005,sign)
Pregnancy rate 72% vs 37% (p value <0.005,sign)
Ifiza etal , hum rep 2002
34. Coasting is one of the very important
tool to prevent OHSS without
compromising clinical outcome
Coasting is equally feasible
with antagonist protocol
Ohss is a serious iatrogenic complication of Art which can be lethal
Various preventive strategies to avoid ohss,Coasting can be done during stm
Boat when reaches near land area ,it sails slowly without any extra effort taking advantage ofprevious energy expenditure
To slide down thru the effect of gravity without consuming energy
Similar manner coasting in ivf is defined as
witholding gn induces apoptosis
Usually coasting can be started in presence of high e2,foll.are 15 or more and diameter of leading follicle is 15 mm and above
Coasting cont till e2 falls to safer level
Systemic review ofVarious studies showing coasting started when e2 level were above 3000,coasting done for 2to 6 days but all studies maintaining a good preg rate.severeohss rate was reduced, although ohss was not totally eliminated but incidence of severe ohss was significantly less
Preg rate were comparable in coasting and non coasting gp .preg rate were not dependant on rate of fall in e2
Coasting can be done safely up to three days ,beyond three days it significantly reduces cpr and IR
Always there is a lack of confidence about early coasting ,chen et at compared early coasting with late coasting .as evident coasting started early and at significantly lesser e2 ,foll size was also sign smaller ,coasting req for more no days but pr & ir was similar in both gpr
Most of the litreture guide us to start coasting when e2 level >3000,but egbase etal has suggested anticipating high e2 and start coasting at lower e2 level so that final e2 on the day of hcg is less and
now the question wether it really reduces the ohss risk. Nafiye has shown that ir and cpr was signif higher in coasted gp than non coasted ,and most imp was the severe ohss rate was sign low in coasted gp .
Is coasting feasible with antag protocol? Farhi etal has shown coasting can be done safely with antg protocoland req for lesser no of days and rapid fall in e2,pr were similar in both gps
ifiza etal has shown simialr IR and PR in recipients with non coaste and coaste donor.thus coasting does not affect embryo quality
Traditionally coasting is done witholding only gn and cont agonist ,but moon etal shown coasting if done by stopping both gn and agonist induce rapid fall in e2 ,coasting is reg for a shorter duration and pr of 44%was maintained
Similar observation were made by basil etal there was sign fall in e2 level when agonist was stopped with gn
He demonstrate endocrine response to withdrawl of agonist ,these graph are showing rapid fall in e2 and no lh surge was noted
